Good afternoon,  I am a new to LaTeX and currently I am writing on my thesis, but I got problems on including my bibliography which is implemented as a .bib file. Probably I should add that there are no errors. I use: TeXworks and Jabref (for creating the .bib file)  Overview of what doesn't work:   Citations in text with correct numerations (i.e. [1]) Attachment of a bibliography section at the end of the document with corresponding entry in the content list     For example: sources.bib  @Book{Schroeder2000,   title     = {Elektrische Antriebe - Grundlagen},   publisher = {Springer Verlag},   year      = {2000},   author    = {D. Schroeder}, }  In my .tex file I want to include this .bib file. So I got something like that (There was a template given to me which contains the following lines, I tried to adjust them for my purposes but it didn't work):  \documentclass[a4paper,11pt]{memoir}  % packages \usepackage{kantlipsum} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{csquotes} % Language \usepackage[english]{babel} %\usepackage[ngerman]{babel} \usepackage{helvet} \usepackage[style=numeric, backend=biber, backref, sorting=none]{biblatex} % use backend=biber if available \usepackage{graphicx} \usepackage{color} % \definecolor{heatred}[RGB}{170,0,0} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{color} \usepackage{siunitx} % \SI{15e3}{\kg}, \SI{0.2}{\m\per\s}, \si{\kWh} \usepackage{mdwlist} % compact lists: \begin{enumerate*}, \begin{itemize*} \usepackage{hyperref} \usepackage{bm} % bold italic symbols in math mode \usepackage{eurosym} \usepackage{pdfpages} \usepackage{tikz}  \addbibresource{sources.bib}  \begin{document}  % table of contents \cleardoublepage \tableofcontents  % content %Include your introduction, etc. \input{tex/01-intro} \input{tex/02-main} \input{tex/03-end}  % Bibliography \clearpage \phantomsection \addcontentsline{toc}{chapter}{Bibliography} \printbibliography  \end{document}   But when I cite in one of my tex documents (i.e. main.tex) it doesn't work.    This is how I cited in my .tex file:  And Mr. P stated that XYZ has happened \cite{Schroeder2000}  This is the output I get from the previous line:  And Mr. P stated that XYZ has happened [Schroeder2000]  Instead of:  And Mr. P stated that XYZ has happened [1]    Additionaly the last part:  % Bibliography \clearpage \phantomsection \addcontentsline{toc}{chapter}{Bibliography} \printbibliography   doesn't work, too. There is no bibliography section in my table of contents and there is no bibliography attached at the end of the document.  I am very sorry if the writing-style doesn't apply to the forum standards. It is my very first time here at this forum. Of course I searched for answered questions but I couldn't find any answers to my problem. I would like to thank you in advance for your help!

Running the minimal example  \documentclass{article} \usepackage{filecontents} \begin{filecontents*}{\jobname.bib} @ARTICLE{example,   author  = {Other, Anthony Norman},   title   = {Some things I did},   year    = {2014},   journal = {J.~Irrep. Res.},   volume  = {1},   number  = {1},   pages   = {1-10} } \end{filecontents*} \usepackage[backend=biber]{biblatex} \addbibresource{\jobname.bib} \begin{document} Hello\cite{example}. \printbibliography \end{document}   I get the warning There were undefined references.  I have read  and know that I need to run:   LaTeX Biber LaTeX   However, my editor is only set up to run BibTeX. How do I go about setting up my editor/IDE to be able to run Biber, and how do I run the LaTeX/Biber/LaTeX cycle?  Answers (sorted alphabetically by editor name)                    Answer guidelines   Each answer should be for one editor. If the editor is cross-platform, if possible give a single answer with notes covering the minor platform variations. Please edit the question to include new answers in the 'link list' Each answer should be 'stand alone', i.e. don't say 'It's almost the same as editor Y but ...' for the editor part Instructions for 'build tools' such as arara or latexmk are welcome but should explain how to set up the editor in question as not all editors allow simple addition of arbitrary tools


Have I got that all the right way round? Anyway, I am parsing a lot of html, but I don't always know what encoding it's meant to be (a surprising number lie about it). The code below easily shows what I've been doing so far, but I'm sure there's a better way. Your suggestions would be much appreciated.  import logging import codecs from utils.error import Error  class UnicodingError(Error):     pass  # these encodings should be in most likely order to save time encodings = [ "ascii", "utf_8", "big5", "big5hkscs", "cp037", "cp424", "cp437", "cp500", "cp737", "cp775", "cp850", "cp852", "cp855",      "cp856", "cp857", "cp860", "cp861", "cp862", "cp863", "cp864", "cp865", "cp866", "cp869", "cp874", "cp875", "cp932", "cp949",      "cp950", "cp1006", "cp1026", "cp1140", "cp1250", "cp1251", "cp1252", "cp1253", "cp1254", "cp1255", "cp1256", "cp1257", "cp1258",      "euc_jp", "euc_jis_2004", "euc_jisx0213", "euc_kr", "gb2312", "gbk", "gb18030", "hz", "iso2022_jp", "iso2022_jp_1", "iso2022_jp_2",      "iso2022_jp_2004", "iso2022_jp_3", "iso2022_jp_ext", "iso2022_kr", "latin_1", "iso8859_2", "iso8859_3", "iso8859_4", "iso8859_5",      "iso8859_6", "iso8859_7", "iso8859_8", "iso8859_9", "iso8859_10", "iso8859_13", "iso8859_14", "iso8859_15", "johab", "koi8_r", "koi8_u",      "mac_cyrillic", "mac_greek", "mac_iceland", "mac_latin2", "mac_roman", "mac_turkish", "ptcp154", "shift_jis", "shift_jis_2004",      "shift_jisx0213", "utf_32", "utf_32_be", "utf_32_le", "utf_16", "utf_16_be", "utf_16_le", "utf_7", "utf_8_sig" ]  def unicode(string):     '''make unicode'''     for enc in self.encodings:         try:             logging.debug("unicoder is trying " + enc + " encoding")             utf8 = unicode(string, enc)             logging.info("unicoder is using " + enc + " encoding")             return utf8         except UnicodingError:             if enc == self.encodings[-1]:                 raise UnicodingError("still don't recognise encoding after trying do guess.")

I received some text that is encoded, but I don't know what charset was used. Is there a way to determine the encoding of a text file using Python?  deals with C#.


You take the blue pill—the story ends, you wake up in your bed and   believe whatever you want to believe. You take the red pill—you stay   in Wonderland, and I show you how deep the rabbit hole goes.   Matrix 1 always got me confused at this point of the movie. This is how I understand the proposition given by Morpheus :  The blue pill   The story ends : the life the matrix invented for you ends. You wake up in your bed : in the jelly tube Believe whatever you want to believe : you are finally free to think for yourself    The Red Pills   You stay in Wonderland : you stay in the Matrix    Then Neo picks the red pill and  I've always been puzzled as why is the red pill the one to get out and not the blue pills. I'd appreciate some enlightenement about this quote : Why is the blue pill the pill to leave the Matrix ?

In The Matrix, when Morpheus offers the blue pill or red pill, he explains:     You take the blue pill - the story ends, you wake up in your bed and believe whatever you want to believe.   The "story" part could be interpreted as "the story of Neo living in the Matrix ends, he wakes up in his "bed" (i.e. the cocoon) and he will have the shock of meeting a reality he might have trouble believing in. This interpretation is wrong, but we could be excused for understanding it that way.     You take the red pill - you stay in Wonderland and I show you how deep the rabbit-hole goes.   Adding to the confusion, staying in Wonderland could mean he would stay in the Matrix, the "wonderful, imaginary place". The rabbit hole took Alice to Wonderland. How deep it goes is precisely to that place. This interpretation is also wrong, but I think we know this only because we know what happens later.  Is Morpheus being deceitful or particularly cryptic? Or were the Wachowskis simply a bit all over the place with the analogies?


More and more often on the Security SE website, I get the same question to review in the "Low Quality" queue, and also the "First Posts" queue?  As a result I often end up first recommending deletion/closure, and then flagging the question as low quality. Shouldn't flagging disqualify me from recommending deletion and vice versa?

Tagging as  as recommended by Shog   Currently, flagging post as very low quality is designed to work :     If more than one VLQ flag accumulates on the post before the review has ended, a number of "Looks Good" responses equivalent to the number of flags is required to dequeue it...         Review items completed by deletion or closing result in a "helpful" status for the flag   Review items completed by "Looks Good" responses result in a "disputed" status for the flag      As a result, reviewer working in the LQ queue can do as follows:   Open the queue item Open the reviewed post in a separate browser tab Flag VLQ outside of the queue Vote "Recommend Deletion" from the queue   Above opens a way to low-risk increase for the count of helpful flags.  Should something be done about this?   Testing for above using  went as follows: after submitting Recommend Deletion and getting Looks Good from next reviewer, flag has been resolved as  and post has been taken off review queue.     Side note. If this is confirmed as a bug, a fix that naturally comes to mind would be to block review completion if flag is discovered at the moment of submitting "Recommend Deletion". Per my recollection, this would be similar to how things work in CV queue - voting to close from outside of the queue while item is still opened blocks "Close" action (reviewer can only Skip and maybe Leave Open).


Im thinking in replace ExtJS 1.2 in a project that does not work in IE9 (only works in compatibility view and is so slowly  loading a tree). What JS frameworks are better (and trying to replacing as little posible the code?  I see ExtJS 4 but has changed a lot compared with ExtJS 1.2

So what I'm looking for is a javascript framework I can use that has several UI controls. I have taken a look at  but those controls are very basic compared to ExtJS. Are there any other competitive alternatives?     This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. More info: .


John has been doing work. Work has been being done by John.  Can we make the passive of Present perfect Continuous tense?  I read in different books that we can not make?

Can the passive voice be used for sentences in the present perfect continuous?  I understand the present perfect and its passive voice (have/has built, has been built). However, the passive voice of present perfect continuous is unclear:   Active: They have been building this house for years. Passive: ???   I have seen suggestions of “This house has been being built for years,” but it sounds awkward and I don't recall anywhere else where two be verbs follow one another. Is this the right form to use?


apt-get is prompting me to remove these packages since they were automatically installed but are no longer required:  libcapi20-3 libgif4:i386 libnss-winbind libp11-kit-gnome-keyring:i386 libpam-winbind ttf-droid ttf-liberation ttf-umefont ttf-unfonts-core winbind wine wine-gecko1.4 wine-gecko1.4:i386 wine1.4 wine1.4-amd64 wine1.4-i386:i386 winetricks   I'm not sure, but wine was installed as a playonlinux dependency. I'm obviously using playonlinux and it is currently installed, so either playonlinux package has messed up dependencies or something else happened.  I could quickly mark wine as manually installed, so apt won't ask me to delete it, but I want to know which packages are no longer requiring these dependencies.  Is there any satanic ritual I can use to achieve this?  Thank you so much in advance!

When packages are already installed and I run an apt-get install <package-name>, sometimes it will print a line <package-name> is set to manually installed.  What does that mean?


If time has a beginning, must it not exist for some amount of "time"? If not, it exists from the point when existence started and if there was ABSOLUTELY no existence there may not exist something that created it, so it makes it obvious that something must exist for infinite amount of time in our universe. Am I wrong?  EDIT:  OK, i will tell you what this question related to in my opinion.  Let's imagine, that the upper theory is right (can exist with all physical issues), so leads to some elements or materials to exist with it, because time cannot exist by its own (if there is nothing, that can change its state the time cant change as well and cant start to create something), so there must be some dimension and time that exist for infinity, and if not there is now way it can physically appear. Am i right? this question relates to physics (for example: if there was no dimension and no time, there was no time and place for big bang, or other thing that changed it to its currently state).  P.S. I know that this is kind of a discussion, but just tell me, are there arguments that make this kind of thing wrong or this is true?  EDIT: Is this purely philosophical questions? I don't think so, but i may be wrong.

Does time stretch all the way back for infinity or was there a point when time appears to start in the universe?  I remember reading long ago somewhere that according to one theory time began shortly before the creation of the universe.  Does time have a starting point of note?


"Avengers" took place in 2012. The start of "Spider-Man: Homecoming" was right after the Battle of New York. In "Civil War", in 2016, it's been 8 years since Iron Man was outed as Tony Stark.  Captain America says he was in the ice for 65 years. That means he was iced in 1946.

The first scene of the movie is presumably set in the immediate aftermath of The Avengers. The movie then fast-forwards to '8 years later'.  But Spider-Man already appeared in Civil War as a high school student, which he still is in this movie. So what's the timeline here? If Avengers was set in 2012 and Civil War in 2016, how can Homecoming be in 2020?  Or am I wrong in assuming the canonical timelines of the other movies?


I am in the process of sending the response to reviews to a journal. It looks like it will take some days for the revision.  In the reviews, the associate editor had commented the following      Finally, I would appreciate if you could submit your revised paper by Jan 12, 2018. If you cannot meet this deadline please contact us (xxx@elsevier.com) to request an extension, otherwise your paper may be withdrawn.   I was wondering if it was OK to write to them asking for an extension or should I somehow submit the revision by Jan 12?

I am a Ph.D. student and presently dealing with my first paper that I had submitted to Scientific Reports.  I received back the reviewer comments together with a note from the editor asking me (as the first author) to revise and resubmit within 4 weeks (exact wording below*). However, my coauthors and I will likely not be able to finish the revision in time (there are only a few days left), and I am wondering how strictly editors stick to these deadlines, and if they are typically likely to close the submission altogether, or rather happy to accept the revision even sometime later. The editor him/herself would obviously be the best person to ask, however, I am not getting a reply to my request for an extension, and I would need to know soon whether to drop everything and just work crazy hours to get the revision to them in time.      We hope to receive your revised paper within four weeks. If you cannot send it within this time, please let us know so that we can close your file. In this event, we will still be happy to reconsider your paper at a later date as long as you haven’t submitted similar or related work elsewhere in the meantime.


I just bought a Samsonite poly-carbonate check in suitcase called Enorme 79 spinner. The dimension quoted in the specs is 22 X 31 X 15 (Inches) that adds up to 68. But the airlines allow only up to 62. When I asked the dealer he said the quoted dimensions include the expandable 5 inches and I can use without expanding the luggage volume.  I am traveling from India to Aarhus, Denmark through KLM airlines.  Should I expect any issues w.r.t. checking in this suitcase?

This question is regarding check-in, not carry-on, baggage.  I'm considering buying a very spacious suitcase measuring 31 x 21 x 15 inches, for a total of 67 inches. This is greater than the 62-inch limit most airlines have [1]. My present suitcase measures 63 inches, which better fits the limit than the one I'm considering buying.  Do airlines actually enforce the size limit for check-in baggage, such as by levying a surcharge? Has this happened to you or to someone you directly know, or is it only a theoretical risk? If it's only a theoretical risk, I'll buy this suitcase.  I've had my check-in suitcase weighed several times, but never had its dimensions measured, as far as I can remember.  [1] Except for Emirates, which recently decreased its limit to 59 inches.


I am getting ready to migrate my data collection (using arduino Yun) from my local virtual server to a live website.  Below are the two files I am using to post and receive data.  There is no need for any human interaction with the data until after it is loaded into the data base. More than one device will be uploading data which why I thought to use the receiver.php file.  I wonder if someone would be willing to help educate me on a secure way to implement the below.  I am not concerned with someone intercepting the data, just don't want someone messing with my database.  post.py (on the Arduino Yun)  #!/usr/bin/python  import sys import sqlite3 as sqlite import requests import json  url = 'http://xxx.xxx.x.x/reciever.php' headers = {'content-type': 'application/json'}  def dict_factory(cursor, row):     d = {}     for idx, col in enumerate(cursor.description):         d[col[0]] = row[idx]     return d  con = sqlite.connect('/mnt/sda1/sensor_flow.db') con.row_factory = dict_factory cur = con.cursor()  cur = con.execute("SELECT * FROM data_log") recs = cur.fetchall() data=dict(payload=json.dumps(recs)) #print data con.commit() con.close()  response = requests.post(url, data=dict(payload=json.dumps(recs)))  print response   Receiver.php (on the Server)  <?php     $servername = "localhost";     $username = "root";     $password = "";     $dbname = "practice";      $conn = new mysqli($servername, $username, $password, $dbname);     if( $conn->connect_error ) die("Connection failed: " . $conn->connect_error);     $payload_dump = $_POST['payload'];      $payload_array = json_decode($payload_dump,true);      if( is_array( $payload_array ) ){          $queries=array();          foreach( $payload_array as $row ){             //get the data_payload details             $device = $row['device'];             $type = $row['data_type'];             $zone = $row['zone'];             $sample = $row['sample'];             $count = $row['count'];             $time = $row['date_time'];             $epoch = $row['epoch_stamp'];              /*note: we do not need to add the semi-colon here as it gets added later when we implode the array */             $queries[]="INSERT INTO `data` ( `device`, `type`, `zone`, `sample`, `count`, `date_time`, `epoch_stamp` ) VALUES ('$device', '$type', '$zone', '$sample', '$count', '$time', '$epoch')";         }         /*             Previously the below query was being execute on every iteration             ~ because $epoch is now the last one encountered in the array,              the value that is updated in ALL records is as it would have been             previously.         */         $queries[]="UPDATE `data` SET `date_time` = from_unixtime( $epoch ) WHERE date_time = 0;";          $sql=implode( ';', $queries );         if ( $conn->multi_query( $sql ) === TRUE ) {             echo "New records created and updated successfully";         } else {             echo "Error: " . $sql . "<br>" . $conn->error;         }     }     $conn->close();  ?>   If my code has problems could you explain why it is a problem as well?  Thank you advance for any and all help!

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I recently found an article about a kind of 'sickness' under   developers that they don't Google before they ask a question but just   ask the question without trying to do research. I'm in a Facebook   group about PHP and 9/10 of all the questions could've been solved by   just searching on Google.      Anyway, I was saying that he should Google it first and then he said   that 'I should chill'. So now I want him to read the article but I   can't find it anymore.      Does anybody know which article I'm talking about?   Where should I post this question?

Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com.


Ubuntu 19.04 is stuck at the ubuntu logo on the boot sequence. I installed it on a Dell Latitude E6540 as the main operating system (not in VirtualBox). It worked normally for few days, and since last night the computer never boots up and gets stuck at this screen.    Please help to recover it.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


In datasheet I observed that forward voltage of diode given as between two values (min and max). In my application the current though the diode is not constant it switches every 15 min(may be more or less).    Is it that the forward voltage remains constant even if the forward current changes ? Does current has any affect on forward voltage?

When you have a diode with a certain barrier voltage (e.g., 0.7 V for Si) and you apply a voltage higher than this barrier potential, why does the voltage across the diode remain at 0.7V?  I understand that the output voltage across the diode will increase as a sinusoidal input is applied until it reaches the 0.7 mark, I don't seem to understand why it remains constant after that point however.  It makes sense to me that any potential greater than this barrier potential will allow current to pass, and correspondingly, the potential across the diode should be the applied voltage minus the 0.7 V.


While working on the draft of a blog post, we've come across this dilemma and, since we're all non-native speakers, we didn't come to a consensus:     Our focus are/is projects that...   We're split pretty much 50/50 between "are" and "is".

My fish's native habitat is rice fields. My fish's native habitat are rice fields.   Which one is correct? I'm pretty sure it's the first, since 'is' modifies 'habitat,' but it still sounds weird...


Several apps come preloaded on the tablet and I want to trash them. What's the way out?

I'm using a Samsung I9000 and I have some annoying apps that came pre installed by the phone vendor, like a music store, a custom web browser and other memory leaking apps.  Those crappy apps can't be uninstalled neither by Manage applications tool, nor by editing the apps tiles in the front menu.  I guess I have to be a root user or something to get rid of those apps, but I don't know how.


How to to play youtube Video in VLC Player. How this possible. we have windows 7 and VLC media player 2.1.3....? like. this video play into VLC

Is it possible for now to watch live youtube video streams using vlc? I just don't want to use flash player. I know that vlc can play youtube videos using link for the page where that video is located, but how about live youtube videos?


I now have an ubuntu server with a user called rvdutchman, I also have a LAMP server running on that server. with using apache2 the dir where you can put your website on is /var/www/html. So I login to the site with the rvdutchman user with ftps. I am in the root, sudo and www-data group. but when I go to that dir I only can copy things from it. when I try to rm or add a dir/file I dont have permissons. Is there anyway I can give the user rvdutchman that permessions?

I want to stop having to use sudo everytime I work in /var/www. How can I do that? I simply want to put all of my sites into this directory and work with them without too much pain.


Having an external monitor connected prevents my Mac from sleeping when I close the lid. Is there any way to opt out this feature?

Up until yesterday (with Snow Leopard), closing the lid would cause my MacBook to sleep whether or not the external monitor was connected.  Since upgrading to Lion last night, closing the lid when the external monitor is attached just tosses all windows to that screen and keeps going.  I realize I can sleep via the Apple menu or keyboard before closing the lid. I'd rather not have to, and I'm wondering if there's a setting to restore the sleep-on-close behavior.


In a problem that I am trying to solve using generating function, the right-hand side (RHS) of the generating function equation is   $\sum_{n=1}^{\infty} (n-1)!x^n$.    Would like to find the closed form for it.  Appreciating any help.

As asked in the title, I am trying to arrive at the generating function   $\displaystyle\sum_{k=0}^{\infty}k!x^k$   just by starting with the generating function with constant 1 sequence $f(x) = \displaystyle\sum_{k=0}^{\infty}x^k$ and using the operation of differentiating $f(x)$ and shifting the terms in the sequence by multiplying $f(x)$ by $x$.  My attempt of the problem (which I believe is wrong).  Start with the following:  $f(x) = \displaystyle\sum_{k=0}^{\infty}x^k$  We differentiating it $k$ times and get  $f^{(k)} = \displaystyle\sum_{k=0}^{\infty}k!x^0 = \displaystyle\sum_{k=0}^{\infty}k!$  Then we shift the terms in the sequence by multiplying $x^k$ to $f^{(k)}$ and we get  $x^kf^{(k)} = \displaystyle\sum_{k=0}^{\infty}k!x^k$. This I believe is wrong because if we look at the $k^{\mathrm{th}}$ partial sum of $f(x)$, then differentiating the $k^{\mathrm{th}}$ partial term $k$ times gives us $k!$ and multiplying this by $x^k$ gives us $k!x^k$, not $\displaystyle\sum_{k=0}^{k}k!x^k$.   I understand the example of how to get from $f(x)$ to getting a generating function of sequence of squares or cubes by differentiating $f(x)$ and multiplying the result by $x$ and repeating this process once more.   If anyone can give me a perspective of how to see this problem or maybe a misunderstanding on my part, I would appreciate it.


Is there any way to move all org metadata (Objects, Apex classes, VF pages, Aura) from Developer Edition to Sandbox? I have started my development in Developer Org, Now i have Purchased new Enterprise Edition, Plan to move all metadata to Sand box. Is there any way, Please guide me in this

I Have only one license of Partial sandbox. I want to refresh it with Production. Before that I want to copy all the metadata present in the Partial sandbox into New/Existing Developer sandbox. How can do that?  Is it supported by salesforce? or are there any tools available for this requirement.  Thanks.


I'm new to blender and started to create something using tutorials. I created an object and added some colors to it then render the object and everything worked fine then I saved it.  But when I opened the saved blender file again it is not showing any of colors but when I render it shows the same object as I saves with colors.  Not sure if something changed in the settings.    The rendered Image:

Why I don’t see colors in object mode on my donut? If I take for example render mode or shading mode, I see them. Moreover if I turn new file blender on and paint cube, I see colors in object mode normally. What’s the matter?


My laptop has an Italian keyboard layout, but after moving to the US I'm using it with a US  keyboard attached via USB when at work. When on the go I'm on the IT keyboard and constantly switching layout for every open program with left-alt+right-shift is becoming a real pain.  Anyone knows of a tool that automatically changes the keyboard layout based on the physical keyboard being used?

I'd like to use multiple keyboards (all USB or one USB and one PS/2) with a different keyboard layout on each. Is this possible in Windows 7 or XP?   I'd prefer to avoid a hardware-based solution if possible.  My specific issue is that I prefer to use a Dvorak layout, but most of my colleagues use QWERTY. I'd quite like it if they could use my computer with a QWERTY layout by using a second keyboard, without affecting the layout of the primary one.


How can I get, from LaTeX, this a4 flyer? I would like to achieve the background colors with TikZ PGF package. Could you help me?  Thank you!

This has bugged me for a while. Are there any packages/templates/methodologies for effectively creating flyers in LaTeX?  Just in case there's some ambiguity in my terminology, I'm looking to create single-page, letter-sized pamphlets/posters, posted to advertise events.  Any ideas?


Can two super capacitors connected in series back to back be used as DC blockers when in series with an AC supply and load, regular polarized capacitors can be used in this mode, but is there something different in the construction of super capacitors which precludes this.If yes are diodes required to prevent reverse charging.

There was some discussion on this question        which I don't see as being conclusively resolved:   "turns out that what might LOOK like two ordinary electrolytics are not, in fact, two ordinary electrolytics." "No, do not do this. It will act as a capacitor also, but once you pass a few volts it will blow out the insulator." 'Kind of like "you can't make a BJT from two diodes"' "it is a process that a tinkerer cannot do"   So is a non-polar (NP) electrolytic cap electrically identical to two electrolytic caps in reverse series, or not?  Does it not survive the same voltages?  What happens to the reverse-biased cap when a large voltage is placed across the combination?  Are there practical limitations other than physical size?  Does it matter which polarity is on the outside?  I don't see what the difference is, but a lot of people seem to think there is one.  Summary:   As posted in one of the comments, there's a sort of electrochemical diode going on:     The film is permeable to free electrons but substantially impermeable to ions, provided the temperature of the cell is not high. When the metal underlying the film is at a negative potential, free electrons are available in this electrode and the current flows through the film of the cell. With the polarity reversed, the electrolyte is subjected to the negative potential, but as there are only ions and no free electrons in the electrolyte the current is blocked. —    Normally a capacitor cannot be reverse-biased for long, or large currents will flow and "destroy the center layer of dielectric material via electrochemical reduction":     An electrolytic can withstand a reverse bias for a short period, but will conduct significant current and not act as a very good capacitor. —    However, when you have two back-to-back, the forward-biased capacitor prevents a prolonged DC current from flowing.  :     For circuit positions when reverse voltage excursions are unavoidable,   two similar capacitors in series connected “back to back” ... will create a   non-polar capacitor function ... This works because almost all the circuit voltage   is dropped across the forward biased capacitor, so that the reverse   biased device sees only a negligible voltage.   :     The oxide dielectric construction that is used in tantalum capacitors   has a basic rectified property which blocks current flow in one   direction and at the same time offers a low resistance path in the   opposite direction.


I would like list dates between two date in a SQL Server stored procedure.  For example:  Date1: 2015-05-28 Date2: 2015-05-31   Results :   2015-05-29 2015-05-30   How to calculate all dates between two given dates?  Regards,

Assume a table structure of MyTable(KEY, datafield1, datafield2...).  Often I want to either update an existing record, or insert a new record if it doesn't exist.  Essentially:  IF (key exists)   run update command ELSE   run insert command   What's the best performing way to write this?


A line to/from a rounded corner ends at the position 'north east' and not at the line around the node.    Is there a simple way to end the line/arrow at the drawn line around A?  MWE:  \documentclass{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture} \node[draw,rounded corners] (A) {A}; \node[draw] (B) at (1,1) {B}; \fill[red] (A.north east) circle(0.5pt) node[font=\tiny, above, anchor =west]{(A.north east)}; \draw[<->] (A) -- (B); \end{tikzpicture} \end{document}

When I use TikZ tree with nodes with rounded corners, the connecting lines do not touch the nodes (near corners) but end where would rectangle end. Is there an easy way around it?  \documentclass{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture} [sibling distance=100]    \node[rectangle, draw, rounded corners = 3]{ }   child { node { } }   child { node { } }   ; \end{tikzpicture} \end{document}


I have to show that for every $x \in \mathbb{R}$ and every $n \in \mathbb{N}$ $$|\sin(nx)| \le n|\sin(x)|  $$ In the previous exercise, I have showed that $|\sin(x)|≤|x|$ with the use of the mean value theorem. I think that I cannot use this approach this time. I also tried to write $\sin(nx)$ as a series expansion but that doesn't work either.     Does anyone know how I can solve this?

Here $n$ belongs to natural numbers. Firstly, I proved the relation by putting $n = 1$ . Then, taking $$|\sin(mx)| \leq m|\sin x|$$ true, I had to prove $$|\sin(m + 1)x| \leq (m + 1)|\sin x|$$  Now, here I got stuck. How to prove it?? Please help.


I am trying to make a random shell in python... But the problem is i get an error with my code i have tried to remove __commands__[0] from my code but then nothing comes. My error: Exception in Tkinter callback Traceback (most recent call last):   File "C:\ProgramData\Anaconda3\lib\tkinter\__init__.py", line 1705, in __call__     return self.func(*args)   File "C:\Users\User1\Downloads\Stuff\untitled2.py", line 14, in commands     if text in __commands__[0]: TypeError: 'set' object is not subscriptable  my code: from tkinter import *  def tk_shell(Name=None):     def commands():         __commands__ = {'-v',                            '-e',                            '+a',                            'DATA'}                           text = (cmd.get("1.0","end"))                           if text in __commands__[0]:             print("version 1.11")                  else:             print("NOPE")                       tk = Tk()     tk.resizable(width=False, height=False)     tk.geometry('700x490')          tk.title('Server Prompt-'+str(Name))          #main     cmd = Text(tk,bg='black',fg='#00FF00')     cmd.config(height=600,width=480)     cmd.pack()               r_button = Button(tk,width=12,height=2,text='Run',bg='#00FF00',command=commands)     r_button.place(x=610,y=0)                         tk.mainloop()  tk_shell()

Which types of objects fall into the domain of "subscriptable"?


As I have never been to Dubai Airport T1, I wanted to ask whether arriving passengers can remain airside and board their onward flight without having to pass immigration. I am well aware that this is possible at T3, since Emirates uses the airport as a hub. But passengers on airlines arriving at T1 will most likely not connect to another flight (or at least not on one ticket and thus most likely need to clear immigration to recheck luggage).  My intention would be to fly the triangle CDG-DXB-AMS for the simple reason of flying on a B787-10. STA from Paris 22:35, STD to AMS at 00:40. With my passport I don't need a visa for the UAE and I would travel with hand luggage only.

Do I need a transit visa for a layover via airports in the UAE, such as Dubai International Airport or Abu Dhabi International Airport? If so, what are the requirements for such a visa? Can I get the transit visa on arrival?


I signed up to Stack Exchange to get help from this community and asked a question. Nobody answered and it was down-voted 10 times by this community. I was wondering what could have I done wrong? Have people lost values? Nobody seems to provide any suggestions of rights and wrongs to the least of which I would have really appreciated. It is cowardice.

Why not make it mandatory to leave a reason or at least a remark of some sort whenever down voting?  You see more and more often questions being down voted while many times they are simply perfectly legitimate, as questions/as people being unable to achieve some desirable result. I am not talking about "Hey, please do this and that for me, thanks :D " posts.  I would like to know what reasons there are for not making it mandatory to leave a reason for a down vote.


$f(0)=0, \ f'(X)$ is a strictly increasing function: prove that $f(X)/X$ is also strictly increasing for all $X \in(0, \infty)$

Let f : [0, 1] → R be a continuous function with f (0) = 0 and suppose that it is differentiable for all x ∈ (0, 1). Further assume that $x \mapsto f'(x)$ is a strictly increasing function on (0, 1). Show that $x \mapsto \frac{f(x)}{x}$ is also a strictly increasing function on (0, 1).


I just noticed that my suggested edits on meta are quickly approved by Community♦, sometimes almost instantaneously.  As a guess: does this have anything to do with the fact that I have edit privileges on the main site?

Why does the Community user sometimes approve or reject edits? How does a machine know if my edit is valid? What does it mean if my edit was rejected by Community?     See also:


I have a dictionary, where each key maps to an array. I want to sort the dictionary based on the highest value in the array of each key. For example, the dictionary: {'r': [2, 2], 'e': [4, 5], 't': [1, 1], 'h': [2, 2], 'y': [1, 2], 's': [0, 1], 'a': [0, 1]}  should become: { 'e': [4, 5], 'h': [2, 2], 'y': [1, 2], 'r': [2, 2], 't': [1, 1], 's': [0, 1], 'a': [0, 1]|

I have a dictionary of values read from two fields in a database: a string field and a numeric field. The string field is unique, so that is the key of the dictionary.  I can sort on the keys, but how can I sort based on the values?  Note: I have read Stack Overflow question here  and probably could change my code to have a list of dictionaries, but since I do not really need a list of dictionaries I wanted to know if there is a simpler solution to sort either in ascending or descending order.


It's clear that Marty first met the 1955 version of Doc by tracking his house down in the phone directory. However, earlier in the film, they are shown to have quite a strong relationship. Doc is happy with Marty coming into his house and even invites him to let himself in.     Doc: This is very important. I forgot my video camera. Can you stop by and pick it up on your way to the Mall?   The fact that they spend time together seems to be common knowledge, to the extent that even the principal of Marty's school says that Marty is "still hanging around" with Doc.     Strickland: Am I to understand that you are still hanging around with Doctor Emmett Brown, McFly?   But how did they get to know each other initially? Their hardly of a similar age and Marty doesn't seem to have any real interest in science or Doc's inventions. Why would he be involved with Doc in the first place?

On the face of it, Doc Emmett Brown and Marty McFly seem to have very little in common.   Marty is active in after school activities, has a beautiful girlfriend and his family, friends and educators all seem to dislike Doc Brown.  Can anybody shed any light on why a seventeen year old boy's best friend would be an elderly nuclear scientist who has been shunned by the respectable scientific community? In a nutshell, how did they meet and why is he still friends with the Doc?


While creating threads I see code like:-  Runnable watdaheck = new Runnable() { System.out.println("java with time contradicts itself"); }   From what I know an interface cannot be instantiated so I fail to understand how we can write Runnable() for creating anonymous class. An interface can be given a reference but cannot be instantiated is what we are taught in polymorphism.

What is the use of anonymous classes in Java? Can we say that usage of anonymous class is one of the advantages of Java?


If $P(x)$ is any polynomial of degree less than $n$, then prove that $$\sum_{j=0}^n (-1)^j\binom{n}{j}P(j)=0$$  My approach was to try and prove this separately for $j^k\ \ \forall\ \ k<n$, instead of $P(j)$, since $P(x)$ can be written as $a_{n-1}x^{n-1}+a_{n-2}x^{n-2}+...+a_0$. However, I could not get anywhere.It would be much appreciated if someone could provide a rigorous solution for this or any key insights.Thanks a lot

Prove that if $p$ is a polynomial of degree at most $n-1$, then   $$\sum_{k=0}^n \binom{n}{k}(-1)^k p(k) = 0.$$  This was probably asked before but I couldn't find it anywhere. Can anyone please help me out here? Looks like the proof is extensive.


Suppose that I want to run a Java program so I would type   java myProgram   and then suppose that it prints some output to the screen but takes a few hours to finish running. If I want to keep working on the same terminal while it runs, what is the command that I should use? I tried & at the end and it did not seem to work.

How do I run a program in the background of a shell, with the ability to close the shell while leaving the program running? Lets say my UI is having problems or for some reason, I need to boot up a program from the terminal window, say, nm-applet:  nm-applet   When it's started, it occupies the foreground of the terminal window.  Is there any simple way to run the program in the background without needing to leave the terminal open or have it occupy the whole terminal?  On that note, I did find a way to run programs from the terminal and have it allow for other inputs, by appending an ampersand (&) to the command as such:  nm-applet &   But this isn't much use as any processes started in the terminal are killed once the terminal is closed.


Capacitors behaving as an open circuits, How can we understand the concept of the Electrons flowing through a capacitors.

I am confused with this! How does a capacitor block DC?   I have seen many circuits using capacitors powered by a DC supply. So, if capacitor blocks DC, why should it be used in such circuits? Also, the voltage rating is mentioned as a DC value on the capacitor. What does it signify?


I am a student and I was introduced to complex numbers about a year ago. I am curious to know whether there is another type of number system more advanced than complex numbers.   So the way I was introduced to complex numbers was by being told the history of numbers. First, there were integers, which were used to count things (such as ten fingers, two eyes, and so on.) Then we came up with decimals that came in handy for example when we say "the glass is half full." Next, we used negative numbers. That was handy in for example in accounting to show debt. Then we came up with imaginary numbers, which are used in, for example, quantum mechanics. So my question is are there any other types of number systems?  Surely, there must be infinite types of numbers. This is because I imagine the real numbers to take up a dimension (similar to the x-axis) and imaginary numbers to take another dimension (similar to the y-dimension.) As a result, I am thinking there must be an infinite type of number because we can add as many dimensions as we like. Am I correct to assume this?

I've been teaching my 10yo son some (for me, anyway) pretty advanced mathematics recently and he stumped me with a question. The background is this.  In the domain of natural numbers, addition and multiplication always generate natural numbers, staying in the same domain.  However subtraction of a large number from a smaller one needs to "escape" into the domain of integers, and division may result in escape to the real domain (like 3 / 5 -> 0.6).  It was a simple step from there to taking the square root of a negative number, hence requiring the escape into the complex domain, such as 4+7i.  He quite easily picked up that each of these domains was a superset of another, natural -> integer -> real -> complex.  However, he then asked if an operation on a complex number would require yet another escape, a question I had to investigate. Now, it turns out that the square root of a complex number is simply another complex number along the lines of mathematical distribution: (a+bi)2 -> a2 + 2abi - b2, from memory.  But I'm wondering if there are other mathematical operations performed on complex numbers (or any of its subset domains) that can't be represented within the complex domain.  Apologies if I've used the wrong terms, it's been about 30 years since I did University level math.


here is the problem   Here is my solution :  $x=y=0$ gives $f(f(0))=f(0)$  $x=0; y=f(0)$ gives $f(f(f(0)=0=f(0)$ (because $f(f(0))=f(0) \iff f(f(f(0)))=f(f(0))=f(0)$)  $x=0$ gives $f(f(y))=-y$  $x=0 ; y=f(y)$ gives $f(-y)=-f(y)\iff f(-f(y))=y$  so $y=-f(y)$ gives $f(2x)=2f(x)$  now we can prove by induction that $f(nx)=nf(x)$  it is true for $n=2$   let's suppose that it is true for $n$   we have $f(nx+f(-f(x))=f(nx)+f(x)\iff f((n+1)x)=(n+1)x$  so it is true now we have $f(x)=xf(1)$   plugging this in the first equation gives $f(1)^2=-1$ which is impossible  I just want to know if my solution is right  In the official solution they prove that $f$ is bijective (which is true because $f(f(y))=-y$ ;) ) then they use cauchy function , they find that $f(x)=cx$ , plugging this in the first equation gives an impossible result.

I'm trying to solve the functional equation $f(x+f(y)) = f(x)-y$ where $f : \mathbb{Z} \to \mathbb{Z}$. What I got so far is: $f$ is injective and $f(0) = 0$. Thanks in advance for your time.


I have my Mac and iPhone linked so I can  send and receive SMS via iMessage on the Mac. Is there a way, for instance a script, that I can use to send a predetermined response whenever an SMS comes in from a specific Cell number?

Is it possible to set up an auto-reply to an incoming text or iMessage, either on my iPhone (or the connected Message app on my Mac)?  Ideally I'd like to customize this depending upon the sender.


So, I am having trouble approaching this question:      Prove that for all natural numbers $n > 2$, there exists a prime number $p$ such that $n < p < n!$    I have been thinking about Bertrand's postulate for some time; however, that theorem cannot be taken as a given in this question. So, I have to actually prove Bertrand's postulate first, before continuing towards the actual claim in the question.   Note: Direct proof, proof by induction, contraposition, exhaustion (cases), contradiction, etc. all ideas and contributions are welcome.

How to prove that there exists a prime number between $n$ and $ n!$, for all $ n> 2$?    ( gives a much better bound, but this question is about obtaining a self-contained proof.)


In my generic list contain integer and string value. how do i perform OrderBy or OrderByDescending.  For example    List<String> codelst = new List<string>() { "1","2","3","4","5","10","100","a12","b12" };   codelst.OrderBy(g => g);   It shows like as follows  1     10   100     2     3     5      a12     b12   but need to show  1         2     3     5     10   100   a12    b12   if I have convert to int it shows input string error  codelst.OrderBy(g => Convert.ToInt32(g));   How to achieve this

Anyone have a good resource or provide a sample of a natural order sort in C# for an FileInfo array?  I am implementing the IComparer interface in my sorts.


I want to search for S+P and replace it with S&P.  Following doesn't seem to be working.  sed 's~"S+P"~"S&P"~' filename1 > filename2

Take the following script:  #!/bin/sh sed 's/(127\.0\.1\.1)\s/\1/' [some file]   If I try to run this in sh (dash here), it'll fail because of the parentheses, which need to be escaped. But I don't need to escape the backslashes themselves (between the octets, or in the \s or \1). What's the rule here? What about when I need to use {...} or [...]? Is there a list of what I do and don't need to escape?


I add this floating numbers in javascript, 1403.07+1000.00 result is 2403.0699999999997  It should be 2403.07  I got a work around (1403.07+1000.00).toFixed(2), but this will fail if precision changes meaning; it will fail for addition of 1403.072+1000.01.  Is there any way I can achieve by jQuery/Javascipt, i dont need external library.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I'm looking for a way to compare two lapses of time.   If the second lapse or part of it is in the first one -> return false. Although, if the first one or a part of it is in the second one -> return false too.   I feel like I didn't have to skive math lessons...  I got   // first lapse $a = strtotime('2016/05/04 22:50'); $b = strtotime('2016/05/20 22:15'); // second lapse $y = strtotime('2016-05-12 12:00'); $z = strtotime('2016-05-20 10:00');  if (($y >= $a && $y <= $b) || ($z >= $a && $z <= $b) || ($a >= $y && $a <= $z) || ($b >= $y && $b <= $z))      return false;   But it's quiet confuse in my brain. I'm not sure it does what it supposes to do. Thank you.  Edit   I found my question was duplicated

Given two date ranges, what is the simplest or most efficient way to determine whether the two date ranges overlap?  As an example, suppose we have ranges denoted by DateTime variables StartDate1 to EndDate1 and StartDate2 to EndDate2.


The following question/answer(s) do not fully cover my question  I have a similar PC I am using for internet, but I would like to try gaming (steam-low spec) too. Here is the result of glxinfo | grep OpenGL: OpenGL vendor string: Intel Open Source Technology Center      OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 400 (BSW)      OpenGL core profile version string: 4.6 (Core Profile) Mesa 20.0.8      OpenGL core profile shading language version string: 4.60      OpenGL version string: 3.0 Mesa 20.0.8      OpenGL shading language version string: 1.30      OpenGL context flags: (none)      OpenGL ES profile version string:  OpenGL ES 3.1 Mesa 20.0.8  OpenGL ES profile shading language version string:  OpenGL ES GLSL ES 3.10  I added some extra specs from glxinfo: Vendor: Intel Open Source Technology Center (0x8086) Device: Mesa DRI Intel(R) HD Graphics 400 (BSW) (0x22b1) Version: 20.0.8 Accelerated: yes Video memory: 1536MB Unified memory: yes Preferred profile: core (0x1) Max core profile version: 4.6 Max compat profile version: 3.0 Max GLES1 profile version: 1.1 Max GLES[23] profile version: 3.1  In the question someone asked earlier, there was no matching answer. Both answers (one in comment) do not match each other. one says profile shading language version string: 4.60 OpenGL version string  determines the shaders your pc has and another answer says to look at OpenGL shading language version string: 1.30  my pc has similar specs, so I would want to know what shaders my pc supports. Also another question: does my pc have OpenGL 4.6 or 3.1? i see two values along two different results from glxinfo?

I am trying to play a Steam game on Ubuntu.  The game requires "Graphics: Shader model 3".  How do I determine if my integrated Intel graphics support Shader Model 3?  At present, when I launch the game, I hear the audio, but the screen is entirely black.  Running glxinfo | grep OpenGL yields:  OpenGL vendor string: Intel Open Source Technology Center OpenGL renderer string: Mesa DRI Intel(R) Haswell Mobile  OpenGL core profile version string: 4.5 (Core Profile) Mesa 18.2.2 OpenGL core profile shading language version string: 4.50 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL version string: 3.0 Mesa 18.2.2 OpenGL shading language version string: 1.30 OpenGL context flags: (none) OpenGL extensions: OpenGL ES profile version string: OpenGL ES 3.1 Mesa 18.2.2 OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.10 OpenGL ES profile extensions:   I am not sure which (if any) of the above lines answer my question.


I would like to insert a function in my code which is begin,commit, and rollback trans because the data is prone to errors. my code is this:  clsDBConnect dbConn = new clsDBConnect(); SqlCommand CMD; SqlDataReader Reader;  private void Save() {      CMD = new SqlCommand("SELECT * FROM tblEmployees", dbConn.connection);       Reader = CMD.ExecuteReader();       while (Reader.Reader())      {           while(variable1 != variable2)           {                //Lots of CMD.ExecuteNonQuery();                //Lots of Reader                //Lots of computation                variable1 += 1;           }      } }   How can I rollback inserts and updates when error occurs during the loop?  Thanks!

What are the best practices to do transactions in C# .Net 2.0. What are the classes that should be used? What are the pitfalls to look out for etc. All that commit and rollback stuff. I'm just starting a project where I might need to do some transactions while inserting data into the DB. Any responses or links for even basic stuff about transactions are welcome.


i want put footnote just margin down no near body text  i find this where i can handle the space between body text and down margin  but is hard calculate space for all my footnotes  \footins\setlength{\skip\footins}{2cm}\footnote{cf. F. P. Ramsey. \textit{The foundations of Mathematics}, London Mathematical Society.}   someone known method for do it automatically?

This is the document:  \documentclass[12pt]{article} \usepackage[top=3in, bottom=3in, left=3in, right=3in]{geometry} \usepackage{lipsum} \interlinepenalty=10000 \begin{document} This is first short par\footnote{foot note}  \lipsum[1] \end{document}   As you can see the foot note is "glued" to the text and is not a "foot" note any more.. How can I make drop it down to the bottom of the page, where it will look like a real foot note?


I can't figure out how to do this. Can anyone give me some hints?

I am trying to prove the following statement:     Let $G$ be a group and $H, K\mathrel{\unlhd}G$. Assuming that $H \cap K =  \{1_G\}$ and $G = \langle H, K \rangle$, prove that $G \cong H \times K$.   From this, we get that $HK \cong H \times K$. Naturally, it would be ideal if I could prove that $HK \cong G$. One issue that I am facing here is the meaning of $G = \langle H, K \rangle$. How is this defined (I mean, more explicitly)? Is my strategy correct or


On 18.04 LTS, I am trying to install AppImageLauncher. When doing so, the following error appears: Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies:  appimagelauncher:amd64 : Depends: libc6:amd64 (>= 2.27) but it is not installable Depends: libcairo2:amd64 (>= 1.2.4) but it is not installable Depends: libcurl4:amd64 (>= 7.16.2) but it is not installable Depends: libfuse2:amd64 (>= 2.6) but it is not installable Depends: libgcc1:amd64 (>= 1:3.0) but it is not installable Depends: libglib2.0-0:amd64 (>= 2.39.4) but it is not installable Depends: libqt5core5a:amd64 (>= 5.9.0~beta) but it is not installable Depends: libqt5dbus5:amd64 (>= 5.0.2) but it is not installable Depends: libqt5gui5:amd64 (>= 5.7.0) but it is not installable Depends: libqt5widgets5:amd64 (>= 5.2.0~alpha1) but it is not installable Depends: librsvg2-2:amd64 (>= 2.14.4) but it is not installable Depends: libstdc++6:amd64 (>= 6) but it is not installable Depends: zlib1g:amd64 (>= 1:1.1.4) but it is not installable E: Unable to correct problems, you have held broken packages.  I have already tried to follow several solutions such as checking the Software & Update configurations and then sudo apt-get update sudo apt-get dist-upgrade sudo apt-get install --install-recommends  Also, I have tried to find the broken packages by: sudo dpkg -l | grep ^..r   And then try to remove them by: sudo dpkg --remove --force-remove--reinstreq package_name  Moreover, because of dependencies again, it doesn't allow it. Even if trying to apply the same to the dependencies. Would anyone know how to solve this? Thank you very much in advance.

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I was trying to install amd graphics drivers and after rebooting now I get just a blank black screen.Someone please help urgently.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I am learning SQlite and I have two classes: DatabaseHelper and MainActivity. The first one is responsible for the database. I would like to create a new table, but in the MainActivity class.   But I am getting this error:   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.database.sqlite.SQLiteDatabase.execSQL(java.lang.String)' on a null object reference   The code is:  DatabaseHelper.java  public class DatabaseHelper extends SQLiteOpenHelper {      public static final String DBNAME = "ABC.db";      @SuppressLint("SdCardPath")     public static final String DBLOCATION = "/data/data/com.example.abc/databases/";     private Context mContext;     private SQLiteDatabase mDatabase;       public DatabaseHelper(Context context) {          super(context, DBNAME, null, 1);         this.mContext = context;     }       @Override     public void onCreate(SQLiteDatabase db) {     }      @Override     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {      }       public void openDatabase() {          String dbPath = mContext.getDatabasePath(DBNAME).getPath();         if (mDatabase != null && mDatabase.isOpen()) {             return;         }         mDatabase = SQLiteDatabase.openDatabase(dbPath, null, SQLiteDatabase.OPEN_READWRITE);     }      public void closeDatabase() {          if (mDatabase != null) {             mDatabase.close();         }      }      public List<ABCMODEL> getListABC() {          ABCModel abcModel = null;         List<ABCModel> abcModelList = new ArrayList<>();        openDatabase();             Cursor cursor = mDatabase.rawQuery("SELECT * FROM abctable ", null);         cursor.moveToFirst();         while (!cursor.isAfterLast()) {             abcModel = new ABCModel(cursor.getString(0),cursor.getString(0));             abcModelList.add(abcModel);             cursor.moveToNext();         }         cursor.close();          closeDatabase();          return abcModelList;      }      }   MainActivity.java       DatabaseHelper mdatabaseHelper;      SQLiteDatabase msqliteDatabase;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          mdatabaseHelper= new DatabaseHelper(this);          File database= getApplicationContext().getDatabasePath(DatabaseHelper.DBNAME);         if(false== database.exists()){             mdatabaseHelper.getReadableDatabase();              if(copyDatabase(this)){                 Toast.makeText(this,"Copy database succes",Toast.LENGTH_SHORT).show();              }else{                 Toast.makeText(this,"Copy database error",Toast.LENGTH_SHORT).show();                 return;             }         }          mdatabaseHelper.openDatabase();          String query;          query=                 "CREATE TABLE abctable2(\n" +                         "Text  TEXT,\n" +                         "Text2 TEXT\n" +                         ");";          msqliteDatabase.execSQL(query);         mdatabaseHelper.closeDatabase();         }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I would like to show that the sequence   $$\frac{n}{(n!)^{1/n}}$$   is monotonically increasing.    I know that this sequence is non-negative, and that it converges to $e$, but I am unable to show that it is increasing.

It is known that when $n\rightarrow\infty$ the sequence $$\frac{n}{\sqrt[n]{(n!)}}$$ has limit $e$ but I don't know how to prove it's monotonicity. After a short calculus using WolframAlpha I found that this sequence is actually increasing. I tried to compare $2$ consecutive members but I couldn't manage to show something. It is obvious that $$\frac{n^n}{n!}$$ is increasing but that don't help us much (I think)


Support proper syntax highlighting for code sections containing  code.

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


If I run sudo apt install gnome-control-center Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  gnome-control-center : Depends: gnome-control-center-data (< 1:3.29) but 1:3.32.2-0ubuntu1.1 is to be installed                         Depends: network-manager-gnome (>= 0.9.8) but it is not going to be installed                         Recommends: gnome-online-accounts (>= 3.25.3) but it is not going to be installed                         Recommends: libnss-myhostname but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Not able to install its dependencies also.


I literally don't remember anything about this except a specific scene where the wise companion keeps correctly guessing how many fingers the protagonist has behind his back.

I used to watch a show about a kid (Named Max maybe?) that was given this magic hat that opened portals at specific spots.  He has a fowl friend (a human who evolved into a bird or something) and a giant gladiator friend who was deathly afraid of spiders (or snakes or something).  It was a cartoon, and I can remember the plot of a few of the episodes if needed, I just can't remember the name.


[pencil/now 3.1.0.ga-2 amd64 [installed,local] This is the result of the command I used to list all the installed apps in ubuntu. But now I need to open the app "Pencil" from the terminal. How can I open it from the terminal? As I tried by its name but it didn't open from terminal.

I would like to know what some specific package installs, for example, when installing ncurses, I have found that TAB key expands:  sudo apt-get install ncurses-   to show:  ncurses-base      ncurses-doc       ncurses-hexedit ncurses-bin       ncurses-examples  ncurses-term   How could I know what, say, ncurses-term installs? I am interested mainly in programs, but libraries and any other filetypes could be useful too.  Command-line method, if possible, would be preferred (any others accepted too).


I have made a class called User with two string attributes: Login and Password.  I have a database (userList, of type ArrayList<User>) with all the existing users, and I want to know if a login is already used or not.  I tried to use lambda expressions in order to do that, but it doesn't work:  ArrayList<String> loginList = null; userListe.forEach(x->loginList.add(x.getLogin()));   How do I solve this?


I would like to know if Blender can be used for 3d reconstruction of CT scans and MRI scans etc.  If so, I would like to be directed to a resource that demonstrates this.  I would like to reconstruct 3D images of various organs of the body based on radiological scans, to also illustrate certain pathologies, for educational purposes.

I know it's possible to do this in BI, but I need your help to do this in cycles. For now, I have a setup to use an image sequence as volume but it only shows 1 slice/frame. I'm using generated texture coordinates for easy mapping (0-1 on each axis). The images are mapped on XY and I would like to use normalized frame# as Z coordinate to map the sequence as a volume.       Images sequence can be found  (I'm using 16-bit TIF files of MRBrain in this exemple).    Any solution is welcome but try to keep it simple and user friendly :).  Final Edit: I had a hard time choosing between Lemon's and PGmath's answers. Lemon's is more user friendly and flexible, and uses the image sequence without any change inside blender. PGmath's uses a 3rd party converter to make the sequence 1 single image, but allows GPU rendering. Well, ImageMagick's command line is : "convert +append *.tif anim.tif" from the folder where the sequence is unzipped. Not so hard. That's why I accepted PGmath's answer.      Now, i played with it, and here's the result.  The "volume" object contains the volume shader (playing with the color ramp gives funny things) and the boolean modifiers (turn them off to see the complete volume, but reduce the final density multiplier for better view). The "Slice Control" arrow empty controls the slice position/rotation. The "Texture Mapping" object controls...the mapping, if it need some tunning (position, rotation, scale, and then tiling if necessary?).


Should I use 'is' or 'are' in the sentence below?      All you need in life is/are coffee and good grammar.   This question is different from  because that question doesn't deal with what verb agreement to use in sentences like this where the subject is "all" (which can be singular, as in "All is well", or plural, as in "All are alike").

My fish's native habitat is rice fields. My fish's native habitat are rice fields.   Which one is correct? I'm pretty sure it's the first, since 'is' modifies 'habitat,' but it still sounds weird...


She was the only one with these tattoos who wasn't sacrificed. I think she became an enforcer, the leader of her tower. She was ridiculed by his peers for allowing different species in. Types of people included lion-like, bird people, and telepaths. I think there were people in power when were elf-like. I only read one book but I think it was a series.

I read this book series in middle school. I believe that it would be classified as young adult fiction/fantasy. A girl has magical powers, and with her growing powers comes runes/tattoos in her arms. This is shown on every book cover. I know that one cover is blue. This one shows the girl in a black tank top and black pants. One is a yellow cover, with her in a dress (I think).  The girl has a friend/mentor, who she develops feelings for. The girl is the key to stopping a war between multiple factions/people. Each side is trying to use her to their advantage. I think the series was written in the early 2000s.


Is the following argument correct?     If $(x_n)$ is bounded and diverges, then there exist two subsequences   of $(x_n)$ that converge to different limits.   Proof. Assume $(x_n)$ is bounded and diverges, then by Bolzano-Weierstrass theorem it follows that $(x_n)$ contains a subsequence $(x_{n_k})$ such that $(x_{n_k})\to\beta$ for some $\beta\in\mathbf{R}$. Now assume that every subsequence converges to the same limit, but then $(x_n)\to\beta$, a contradiction, thus we must have another subsequence $(x_{n_r})$ such that $(x_{n_r})\to\alpha$ and $\alpha\neq\beta$.   $\blacksquare$

Let $(x_n)$ be a bounded but not convergent sequence. Prove that $(x_n)$ has two subsequences converging to different limits.    My attempt is:  Since the sequence is bounded , there exists $M>0$ such  that $x_n \in [-M,M]$ for all $n \in \mathbb{N}$. Since the sequence does not converge to $x$, there exists $\epsilon_0>0$ such that $ \forall N \in \mathbb{N}$, there exists $n \geq N$ such that $|x_n-x| \geq \epsilon_0$.   Then we have $x_n \in [-M,x-\epsilon_0] \cup x_n \in [x+\epsilon_0,M]$. By Bolzano-weierstrass theorem, there exists a convergent subsequence in the two intervals.   Is my proof valid? ${}{}$


I have a lot of classes that extend an abstract base class. I would like to automatically create an instance of each one and add them into an array list of base class objects, so when I need to iterate through the list I can call the same method and do something else depending on what derived class the current object is. The problem is how to instantiate everything automatically as the number of derived classes can be high, about 40-50, maybe more afterwards. Any help would be appreciated.  EDIT: I added a commentary in which I explained more details about the question

I want to do something like this:  List<Animal> animals = new ArrayList<Animal>();  for( Class c: list_of_all_classes_available_to_my_app() )    if (c is Animal)       animals.add( new c() );   So, I want to look at all of the classes in my application's universe, and when I find one that descends from Animal, I want to create a new object of that type and add it to the list.  This allows me to add functionality without having to update a list of things.  I can avoid the following:  List<Animal> animals = new ArrayList<Animal>(); animals.add( new Dog() ); animals.add( new Cat() ); animals.add( new Donkey() ); ...   With the above approach, I can simply create a new class that extends Animal and it'll get picked up automatically.  UPDATE: 10/16/2008 9:00 a.m. Pacific Standard Time:  This question has generated a lot of great responses -- thank you.  From the responses and my research, I've found that what I really want to do is just not possible under Java.  There are approaches, such as ddimitrov's ServiceLoader mechanism that can work -- but they are very heavy for what I want, and I believe I simply move the problem from Java code to an external configuration file. Update 5/10/19 (11 years later!) There are now several libraries that can help with this according to @IvanNik's   looks good. Also  from @Luke Hutchison's  looks interesting. There are several more possibilities in the answers as well.  Another way to state what I want: a static function in my Animal class finds and instantiates all classes that inherit from Animal -- without any further configuration/coding.  If I have to configure, I might as well just instantiate them in the Animal class anyway.  I understand that because a Java program is just a loose federation of .class files that that's just the way it is.  Interestingly, it seems this is  in C#.


I know that when there is close to zero variance in either random effect, a perfect correlation can mean that the model isn't able to estimate both effects.  However, I have a good deal of variance in my random intercept and slope. They are, however, perfectly correlated.  I've read some conflicting advice on whether this is a problem.   says: You should be trying to select the 'minimal adequate' model; in particular, overfitting the model (including zero and/or perfectly correlated terms) is more likely to lead to numeric problems, so it's better to try to reduce the model until all the terms can be uniquely estimated.   says:  In general, however, large positive or negative correlations among random effects can reflect structure in one's data and I would certainly recommend against taking out random correlations on the basis that they're close to ±1 when they're included in the model!  (Though this seems to be talking about a correlation close to 1, and not one that is exactly equal to 1?)  Finally, there is some advice offered : This is a standard symptom of an overfitted model. what to do about it (suppress correlation, remove random slope term, penalize using blme package) isn't as clear. glmm.wikidot.com/faq might have some useful information.  So I am wondering:  1) Is this a problem? The correlation actually makes sense given my data, but is there an issue with keeping this correlation in my model?  2) What should I do? The last comment is from Ben Bolker in 2014. Is that still the prevailing advice on what to do?

Not so uncommon occurrence when dealing with complex maximal mixed models (estimating all possible random effects for given data and model) is perfect (+1 or -1) or nearly perfect correlation among some random effects. For the purpose of the discussion, let's observe the following model and model summary   Model: Y ~ X*Cond + (X*Cond|subj)  # Y = logit variable   # X = continuous variable   # Condition = values A and B, dummy coded; the design is repeated  #             so all participants go through both Conditions   # subject = random effects for different subjects    Random effects:  Groups  Name             Variance Std.Dev. Corr               subject (Intercept)      0.85052  0.9222                              X                0.08427  0.2903   -1.00                      CondB            0.54367  0.7373   -0.37  0.37                X:CondB          0.14812  0.3849    0.26 -0.26 -0.56 Number of obs: 39401, groups:  subject, 219  Fixed effects:                  Estimate Std. Error z value Pr(>|z|)     (Intercept)       2.49686    0.06909   36.14  < 2e-16 *** X                -1.03854    0.03812  -27.24  < 2e-16 *** CondB            -0.19707    0.06382   -3.09  0.00202 **  X:CondB           0.22809    0.05356    4.26 2.06e-05 ***   The supposed reason behind these perfect correlations is that we have created a model which is too complex for the data that we have. The common advice that is given in these situations is (e.g., Matuschek et al., 2017; ) to fix the overparameterized coefficients to 0, because such degenerate models tend to lower the power. If we observe a marked change in fixed effects in a reduced model, we should accept that one; if there is no change, then there is no problem in accepting the original one.  However, let's presume that we are not interested only in fixed effects controlled for RE (random effects), but also in the RE structure. In the given case, it would be theoretically sound to assume that Intercept and the slope X have non-zero negative correlation. Several questions follow:   What to do in such situations? Should we report the perfect correlation and say that our data is not "good enough" to estimate the "real" correlation? Or should we report the 0 correlation model? Or should we maybe try to set some other correlation to 0 in hope that the "important" one will not be perfect anymore? I don't think there are any 100% correct answers here, I would mostly like to hear your opinions. How to write the code which fixes the correlation of 2 specific random effects to 0, without influencing the correlations between other parameters?


I have two server one is production abc.com other demo.abc.com problem is Google has indexed the demo server as well.   What is fastest possible fix to it and to remove it from Google index?  What harm it has given to my live site and is that possible to recover in future?  Thanks

We have a staging version of our website to test changes on at trailheadpaddleshack.ca/staging1. This never appeared in search before. Recently the staging site has appeared on Google and is affecting our search results.  I'm trying to figure out how the pages got there and how to remove them. The pages have always had <meta name="robots" content="noindex, nofollow"> in the head.  I am kinda new at this but was under the impression this should prevent Google from showing my site in results. I am pretty sure the results appeared in google after I accidently copy pasted some codes from the staging site to the live site that contained links to pages on the staging site. If anyone can point me in the right direction to figure out what happened and prevent it from happening again would be much appreciated.  robots.txt looks like this:  User-agent: * Disallow: /calendar-2/action~posterboard/ Disallow: /calendar-2/action~agenda/ Disallow: /calendar-2/action~oneday/ Disallow: /calendar-2/action~month/ Disallow: /calendar-2/action~week/ Disallow: /calendar-2/action~stream/ #Begin Attracta SEO Tools Sitemap. Do not remove sitemap: http://cdn.attracta.com/sitemap/4035112.xml.gz #End Attracta SEO Tools Sitemap. Do not remove   I also tried adding an X-Robots-Tag header and submited the site to be re-crawled. Did that a few days ago and I still see no changes. Here are the HTTP headers according to "Fetch as Google":  HTTP/1.1 200 OK X-Robots-Tag: noindex,nofollow Vary: Accept-Encoding Transfer-Encoding: chunked Date: Sun, 24 May 2015 16:26:49 GMT Server: LiteSpeed Connection: close X-Pingback: http://trailheadpaddleshack.ca/staging1/xmlrpc.php Content-Type: text/html; charset=UTF-8 Link: <http://trailheadpaddleshack.ca/staging1/?p=170>; rel=shortlink   I am now faced with a bunch of results I need to remove from Google asap as they contain out of date information and are affecting our search results. Webmaster Tools has something for removal of a single URL but I am looking to remove the entire /staging1/ subfolder. Any tips?


We know that a p-value can be interpreted as the probability of seeing the same response given that the null hypothesis is true.   p-value is not the probability of making a type 1 error. (as emphasized here: )  However, the significance level, alpha, we know corresponds to the probability type 1 error.  How does it make sense to make comparison with alpha and p-value? They represent to different probabilities.

I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error.  I understand that p-values are defined as "the probability of obtaining a test statistic at least as extreme as the one we actually observed", while a significance level is just an arbitrary cutoff value to gauge if the p-value is significant or not. Type I error is the error of rejected a null hypothesis that was true. However, I am unsure regarding the difference between significance level and the type I error, are they not the same concept?  For example, assume a very simple experiment where I flip a coin 1000 times and count the number of times it lands on 'heads'. My null hypothesis, H0, is that heads = 500 (unbiased coin). I then set my significance level at alpha = 0.05.  I flip the coin 1000 times and then I calculate the p-value, if the p-value is > 0.05 then I fail to reject the null hypothesis and if the p-value is < 0.05 then I reject the null hypothesis.  Now if I did this experiment repeatedly, each time calculating the p-value and either rejecting or failing to reject the null hypothesis and keeping a count of how many I rejected/failed to reject, then I would end up rejecting 5% of null hypotheses which were in actuality true, is that correct? This is the definition of type I error. Therefore, the significance level in Fisher significance testing is essentially the type I error from Neyman-Pearson hypothesis testing if you performed repeated experiments.  Now as for p-values, if I had gotten a p-value of 0.06 from my last experiment and I did multiple experiments and counted all the ones that I got a p-value from 0 to 0.06, then would I also not have a 6% chance of rejecting a true null hypothesis?


I have a JavaScript object. Is there a built-in or accepted best practice way to get the length of this object? const myObject = new Object(); myObject["firstname"] = "Gareth"; myObject["lastname"] = "Simpson"; myObject["age"] = 21;


Let $f$ be three times differentiable on $[a,b]$. $f'''$ is continuous. Show that there is a $c\in[a,b]$ such that $$f(b)-f(a) =((b-a)/2)\cdot(f'(a)+f'(b))-((b-a)³/12)\cdot f'''(c)$$  This looks like a combination of Mean Value Theorem and Taylor's series. but how to solve it, i don't know. Thanks for any answers!

Let $\,f$ be three times differentiable on the interval $[a, b]$. Show that there is a $c$ such that: $$f(b) - f(a) = \frac{b-a}{2}(f'(a)+f'(b)) - \frac{(b-a)^3}{12}f'''(c).$$ Answered in the comments.


I have been curious about a usage of the word "king".  a country where football is king () In mergers and acquisitions, cash is king. ()  This is a very common usage, but it doesn't seem to accord with dictionary grammar. According to both  and , the noun king is a count noun. But the absence of an article here suggests it is either used uncountably, or even adjectivally. Are dictionaries wrong? Which case is it? Another slightly different example is as follows:  It is widely considered to be king of the supermarket chains. (ibid.)  These sentences read perfectly natural and idiomatic to me, but I am still wondering, if "king" is a noun here, why is it not preceded by the definite article?

I've heard people say "be king" (as in "I can't wait to be king") in movies and TV. Why don't they say "be a king"? Which is correct?


The basic goal is to write a function as such: int myInt = 5; PrettyPrint(myVar);  //in some helper class public static void PrettyPrint<T>(T var) {     Console.WriteLine(/* ??? */ + ": " + var); //output: "myInt: 5" }  I know we can do nameof(myVar) inline which would return "myVar", however, is it possible to abstract that into a function that lives somewhere else? If we do nameof in PrettyPrint, in this case it would return "var" and not the original name. Now, I know you're thinking "just pass in a string for the name", but ultimately I'd like the following: public static void PrettyPrintMany<T>(params T[] vars) {     string s = "";     foreach (T v in vars) {         s += <original name> + ": " + t + " | ";     }     Console.WriteLine(s);  }  int myInt = 5; string myStr = cheese; float myFloat = 3.14f;  PrettyPrintMany(v1, v2, v3); //"myInt: 5 | myStr: cheese | myFloat: 3.14 | "  I feel like this is not possible, but maybe there is some clever hackery that can be done?

Let me use the following example to explain my question: public string ExampleFunction(string Variable) {     return something; }  string WhatIsMyName = "Hello World"; string Hello = ExampleFunction(WhatIsMyName);  When I pass the variable WhatIsMyName to the ExampleFunction, I want to be able to get a string of the original variable's name. Perhaps something like: Variable.OriginalName.ToString()  Is there any way to do this?


I’m a newbie with this Ubuntu system, I often use windows.. anyway my uncle gave me a laptop which uses Ubuntu 10 or something and I updated it to 12.04.  the system popped out this Ubuntu one and I clicked the install button yet several minutes some error came out as seen below.  W:Failed to fetch cdrom://Ubuntu 10.04.1 LTS_Lucid Lynx_-Release i386 (20100816.1)/dists/lucid/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs ,W:Failed to fetch cdrom://Ubuntu 10.04.1 LTS_Lucid Lynx_-Release i386 (20100816)/dists/lucid/restricted/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs ,E:Some index files failed to download. They have been ignored, or old ones used instead.   can someone help me with this?

I have a warning triangle on the top of my screen. When I click on it, it says that my update information is outdated. When I type sudo apt-get update && sudo apt-get upgrade into a terminal, I get this message:  W: Failed to fetch cdrom://Ubuntu 14.04 LTS _Trusty Tahr_ - Release i386 (20140417)/dists/trusty/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  W: Failed to fetch cdrom://Ubuntu 14.04 LTS _Trusty Tahr_ - Release i386 (20140417)/dists/trusty/restricted/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  E: Some index files failed to download. They have been ignored, or old ones used instead.   Any ideas?


I'm having a weird glitch i believe. I'm new to blender and was fiddling around, practicing with a random helmet mesh and added a boolean intersection into the helmet. After this, when I am in edit mode (with wire-frame turned on, a trigon in my mesh is not showing, but when i switch over to object mode the hole disappears. I checked face selection (hotkey 3) to see if there was a duplicate helmet or surface covering up the face but there is nothing. Is this a glitch? My blender file:

I have append a mesh (rex) from this .blend .  In edit Mode I see different vertices from objcet mode (see pictures). The vertices of belt are missing!  OBJECT MODE:   EDIT MODE:   How can I edit vertices of belt? Is It a bug?  This is my .blend  maybe can help.


I can't log in to my Ubuntu computer after it enters sleep mode. If I hard reboot I can log in.  What could be the problem, and how can I fix it?

Did a fresh install of Ubuntu 17.10 a few days ago on my Lenovo Thinkpad Edge (using an existing home directory on a different partition).  When I close the lid and put it to sleep, on waking it I can no longer login. Sometimes it spends ages checking the password, then says the password is wrong. Sometimes I can't even enter anything into the password box. To fix this I have to shut down and restart. Login always works fine on a restart.  Any help?


I want to find the color group of blue removed from Image 2 compared to Image 1.   and

I want to extract/mark/show all blue colors of the image because there are color blinds who see them as black/wrongly.  I need to estimate all blue-bluish colors there and be able to change the color group to some other colors if necessary.  I cannot change all bluish colors to something else but need to find some compromise.  I heard that you can do it by Photoshop (any edition) but I cannot find a way to do it.


I seem to be getting a more precise version of a double value for certain numbers.   For example, 69.55554, when assigned to a double variable is saved as 69.555539999999993  I have even tried using NSNumber and NSDecimalNumber instead, to no avail. I'm using swift and haven't tested out the same using objective-c.  Any idea on why this occurs and how to fix it (or work around it)? Thanks!  Code Sample where I used NSDecimalNumber  var doubleNumber  : Double  =   69.55554 var decimalNumber           =   NSDecimalNumber(double: doubleNumber)  var label   =   UILabel(frame: CGRectMake(10, 20, 200, 40)) label.text  =   "\(decimalNumber.doubleValue)" self.view.addSubview(label)

double r = 11.631; double theta = 21.4;   In the debugger, these are shown as 11.631000000000000 and 21.399999618530273.  How can I avoid this?


Imagine I have have a struct with 9 properties, which return a value type as its result and in that struct I also have a property which returns a reference type : IEnumerable like this:  public IEnumerable<KeyValuePair<String, String>> Dostuff         {             get             {                 //doing some operations in here                 return _valueToReturn;             }         }   Using IEnumerable will require heap space, but actually the struct is based on the stack, so what to do in my case?  By the way the struct is immutable.

When should you use struct and not class in C#? My conceptual model is that structs are used in times when the item is merely a collection of value types.  A way to logically hold them all together into a cohesive whole.  I came across these rules :   A struct should represent a single value. A struct should have a memory footprint less than 16 bytes. A struct should not be changed after creation.   Do these rules work? What does a struct mean semantically?


I have one problem, i wan't to add image and vertical center align image. This looks like this   I wan't to look like this:   My code:
Test
   I tried this, but is there some better way to fix this problem?  p {     display: inline-block;     margin-bottom: -1.76em;   }

Why won't vertical-align: middle work?  And yet, vertical-align: top does work.   span{   vertical-align: middle; }
      Doesn't work.


So, this is the code I've got difficulties with:  import optarse import subprocess  def get_arguments():     parser = optparse.OptionParser()     parser.add_option("-i", dest="interface")     parser.add_option("-m", dest="new_mac")     (options, arguments) = parser.parse_args()  def change_mac(interface, new_mac):     subprocess.call(["ifconfig", interface, "hw", "ether", new_mac])  change.mac(options.interface, options.new_mac)   As far as I know, the variables options & arguments are storing the values of whatever parser.parse_args() returns. Now, whenever I call this program in my terminal, it's giving me an error. It's saying that the name options is not defined. How is this possible?   PS: I know the solution is to work with return parser.parse_args(), but I'm just trying to understand why the (options, arguments) = parser.parse_args() doesn't work.  Thanks in advance!

What exactly are the Python scoping rules?  If I have some code:  code1 class Foo:    code2    def spam.....       code3       for code4..:        code5        x()   Where is x found?  Some possible choices include the list below:   In the enclosing source file In the class namespace In the function definition In the for loop index variable Inside the for loop   Also there is the context during execution, when the function spam is passed somewhere else. And maybe  pass a bit differently?  There must be a simple reference or algorithm somewhere.  It's a confusing world for intermediate Python programmers.


Find all functions  $f: \Bbb{R} \to \Bbb{R} $ such that $f(f(x)) = -x$.   I think this equation has no continuous solution, because no polynomial can be the solution and we know that every continuous function is the limit of a sequence of polynomials.

Is there a function $f\colon \mathbb{R} \to\mathbb{R} $ such that $ f(f(x)) = -x$ ?


My assumption here is that in the definition of elementary work :  $dW = F ds$ symbol $d$ represents a differential.  But a  differential implies a function :  $dy =_{df} d[f(x)] = f'(x) \Delta x = f'(x)dx$.  This is why, in order to better understand the notion of " elementary work" ( and in general, " elementary quantty" , such as " elementary displacement, etc. ), I'd like to express elementary work as the differential of a function.  Is this possible?  It seems to me that the function should have distance ( " s") as independent variable. Is it the case?   My question is not much about work than in the notation that (I believe) is used to define other physical quantities. In University Physics ( vol.1) I find this ( with $dW$ standing for "increment of work", and $d\vec r$ standing for infinitesimal displacement): $$dW= \vec F . d\vec r$$ (Source: text page 328 of ) (In the Wikipedia article, I find the same thing with "$\delta W$" instead of "$d W$", so $ \delta W = Fds$). Should $dW$ (or $\delta W $) be understood as a differential (defined as: $dy = d[f(x)] = f'(x) dx$)? I mean, is it correct to read the equation as a definition of the differential of the work function, say $W(s) =$ work done for a distance $s$? Can the equation $d W= Fds$ be read as: $$d(W(s)) = Fds~?$$ I guess I am wrong since, being given the general definition of a differential (i.e. $dy=d[f(x)] = f'(x)dx$), my last line would mean: $$ d[W(s)] = W'(s)ds= F ds$$ implying that force $F$ is the derivative of work (which I don't think is true). In brief (1) I don't understand the "small change" / "infinitesimal change"  interpretation of $d$ (2) and the "differential" interpretation does not seem to work either. So, please, what does $d$ rigorously mean? (Sorry, my style certainly lacks clarity, due to the confusion I'm in regarding this $d$-notation). PS: another interpretation is that $dW$ is a derivative of the work function (since work is defined as the integral of $dW$). But in that case, why not use the ordinary derivative notation?

I have read the thread regarding , but it does not answer my question.  I am confused about the notation for change in Physics. In Mathematics, $\delta$ and $\Delta$ essentially refer to the same thing, i.e., change. This means that $\Delta x = x_1 - x_2 = \delta x$. The difference between $\delta$ and $d$ is also clear and distinct in differential calculus. We know that $\frac{dy}{dx}$ is always an operator and not a fraction, whereas $\frac{\delta y}{\delta x}$ is an infinitesimal change.   In Physics, however, the distinction is not as clear. Can anyone offer a clearer picture?


I am using a Macintosh keyboard on Windows and would like to create a hotkey so that I can turn ctrl and some other other button into the “right click context menu” button of non-mac keyboards.  What would such a script look like?  Let’s say I want to make ctrl+R as the “right click context menu” command.  I know the usage of AutoHotkey so I just want to know what the script would look like.

I am trying to use my HTPC with only a keyboard. Even though my keyboard is from Microsoft, they failed basic windows certification and did not include a menu-key, the one that shows a mouse cursor and a menu, usually located on the right of the space bar, between alt and control. without that i can't do many actions. On windows XP (or maybe NT? not sure) right alt+enter used to emulate that key and i would get the context menu... but on windows 7 that ain't so. Is there any other key combination that can act as an alternative for context menu on selected items on windows 7?


I have a score of some feature, $F_1$ and $F_2$ where this score is the logarithm of probability.  This score is very low and very sparse, for example i have:  $F_1$ with score $-800$  $F_2$ with score $-3000$  I need to get the probability with the exponential function and make the sum of probability like this:  $e^{-800} + e^{-3000}$  But if I make the exponential of this number i get 0 for the underflow problem. With log-sum-exp trick i can do:  $\log(e^{-800}+e^{-3000})$  $= \log(e^{-800+800}+e^{-3000+800})-800$  $= \log(e^{0}+e^{-2200})-800$  But now i have $e^{-2200}$ that is too small.   What's wrong? how I can make my $e^{-800} + e^{-3000}$ sum ?

In some problems, probabilities are so small that they are best represented in computational facilities as log-probabilities.  Computational problems can arise when you try to add these small probabilities together, since some computational facilities (e.g., base R) can't distinguish very small probabilities from zero.  In these cases it is necessary to solve the problem either by finding a workaround that avoids the small numbers, or by using a computational facility that can deal with very small numbers.  The archetypal problem of this kind is as follows.  Suppose you have log-probabilities $\ell_1$ and $\ell_2$, where the corresponding probabilities $\exp(\ell_1)$ and $\exp(\ell_2)$ are too small to be distinguished from zero in the initial computational facility being used (e.g., base R).  We want to find the log-sum of these probabilities, which we denote by:  $$\ell_+ \equiv \ln \big( \exp(\ell_1) + \exp(\ell_2) \big)$$  Assume that we are ---at least initially--- working in an environment where $\exp(\ell_1)$ and $\exp(\ell_2)$ cannot be computed, since they are so small that they are indistinguishable from zero.  Questions: How can you effectively compute this log-sum?  Can this be done in the base R?  If not, what is the simplest way to do it with package extensions?


In fluid mechanics, the drag force is determined by the product between the drag coefficient, the dynamic pressure, and the reference area.  My question is how can I know what geometric area to use as the reference area?  (I had read the post regarding the reference area of a parachute but it doesn't give me a clear answer, should I look up the drag coefficient, then calculate back to find the reference area?)

In many fluid-dynamics models and quantities (, ... generally various  descriptions) there is a parameter (usually $L$ or $\ell$) descripted as characteristic linear dimension or characteristic length. What is that in intuitive and physical meaning? I understand the typical examples ( etc.) but I can't see so far any systematic generalisation.  What is the definition? (Or, maybe: What is its role during the derivation?)