How can I make my branding color palette from primary colors?  This is the url with the logo and the primary colors:   How can I make other colors?

No matter how nice the composition, flow, and lines of my design are, if I am not copying directly from nature, I have a very difficult time picking a decent color scheme.  It either looks too drab, or too garish.  Is there a good resource that will help me to choose a color scheme that has 2 or 3 colors, and the colors do not clash?  I'm not looking for specific colors or color schemes.  What I need is a resource that will help me choose a color (or colors) that go nicely with, or provide a good accent to, whatever main color I am working with on the design.


If I have an old house, as in 80 years old (the wiring is newer than that), and it only has two wires, hot and neutral, no ground, can I connect newer things like ceiling fans or hanging lights? The house wiring isn't 80, but it is old enough to have Wadsworth breakers.  The outlets are not grounded, and someone said if I get GFCI outlets this will ground the outlet (put on in each room they said.)  One person said if I don't, my computer and electronics will get surges or fry.  The house is grounded, but not the receptacles. I really did not want to rewire the whole house.  The wiring itself is good, not paper sheathing the electrician said.  This particular electrician said it would be "ok" and he wouldn't worry about plugging in things like computers or get a UPS.  The electrician also said even though a couple of the GFCI outlets in a bathroom were ten years old that they still trip and are ok. Does the house have to be rewired to use modern electrical devices (lights, tv, refrigerators, computers, etc.)?

I don't know too much about replacing outlets, only what I've read online or through YouTube videos. The house was built in the early 50s. Some outlets have been replaced (brand new kitchen)  but some are still the old 2 prong. I bought a receptacle tester and tested the newer style outlets, which all tested as correct wiring. Upon opening and inspecting, none of these new 3 prong outlets had no ground wires. Does this mean the boxes are already somehow grounded? I'm even more confused now that the receptacle tester said that they were correct. Please help!


I'm have connectivity issues with the Google Play Store app.  I have a non-rooted Note 3 (4.3).  The had worked the first few weeks I had the phone in December and then hasn't worked since.  I get the same "No connection - Retry" error everytime I access it.  I've been have trouble with Google Play Services since I tried disabling it when I realized how much battery life it drained.  I've had trouble using Youtube at times but never as persistent and consistent as the Play Store.  I have done the following:   Wi-fi/LTE connections, no difference between the two Airplane mode on/off Manual and automatic date/time Updated both Google Play Services and Google Play Store via Android Police   I have basically done everything except a factory reset which seems like the next logical step but it does not fix the problem for everyone.  I am trying to figure out if there is anything else I haven't tried that I may be overlooking.  Thank you!

I have an HTC Desire HD. I am having trouble connecting to the Google Play Store. Every time I try to connect it just come up with an error "NO CONNECTION". I really want to download some apps (in particular Words With Friends). I know I am connected to the Internet; I can access my mail and Facebook, etc.   I have uninstalled Play Store and re-installed it but no luck!  How can I fix this?


I'm thinking of for example making the jump action of a character, that takes ~1s, a distinct runnable, so then other threads can read its state, with additional control over the action itself by the "action thread". Are people doing this? What is there to consider when thinking about creating and destroying hundreds (or thousends) of threads a second in a bigger game or other application?

I developing a simple real-time strategy game in a small team with no experience, and we're considering using one thread per game object (tank, soldier, etc). Is this a good idea or is it overkill?  The thread would call each object on each instant change (game timer, not graphic engine timer)  We're using Python with the Panda3D engine, meaning the GIL is probably going to reduce a lot the possible speed improvements.


I tried to su to root so I could install lights, but I get an authentication error when I try:    user@host:~$ su Password:  su: Authentication failure

How do I gain root privileges in Ubuntu Desktop 12.04? I installed to a USB stick to try it out. Now when I installed it on a VM, I don't have the same options as I did on the USB stick, such as opening remote desktop, installing drivers, and some of the video capabilities.


The other day, I was hunting for a word to describe someone I know. The trait denoted by this word is the tendency to rapidly spot--as though unconsciously seeking out--double meanings, especially of the racier sort, in messages whose intent was probably innocuous.

I’m looking for ideally a single word that describes with positive connotation a highly empathetic and witty person — the type of person who’s a fantastic conversationalist as a result of these qualities. What describes that person who can masterfully pick up on the subtle nuances of a conversation, and then respond appropriately, empathetically, quickly, and keenly?  After scraping the thesaurus around empathetic, witty, smooth, sharp, sagacious, etc I could not come up with anything that fit the association well.  Empathetic didn’t imply the good-to-talk-to, conversational properties. Witty in the context of conversation brings up thoughts of interesting facts, word puns, and trite remarks without much association with one in tune with the nuances of how the other person is thinking.  As an aside, I feel like this word would be extremely useful to me. Anyone who exemplified in the qualities that this word is trying to convey would be an interesting person to talk to.


I do have a lot of strings with special regex characters. An examples:   - Test1 + Test2 -> plus should not be a regex special character but a normal character   Is there a Java regex method to escape all regex special characters?

Does Java have a built-in way to escape arbitrary text so that it can be included in a regular expression? For example, if my users enter "$5", I'd like to match that exactly rather than a "5" after the end of input.


As an avid fan of folk, metal and especially folk metal, I encounter many foreign languages and dialects on a daily basis. As I would like to understand what I'm hearing to the best of my ability as an English-only speaker, it would be very convenient if I didn't have to propose a new site on Area 51 every time I'm confused about a lyric. Unfortunately, it looks like SE prefers sites for individual languages as opposed to groups of languages, and Google Translate is not a native Swede, nor does it translate Sognamål.  Where can I ask this kind of question so that native speakers and cultural experts will see it?  P.S. I really don't think the folks over at Music Fans would be able to help much with translation stuff.

Is there a community to ask about translation, especially about Hebrew translation?   I didn't find any community that I can ask about such translation tools or general inquiries.


There is a question in my  (Q. No. 11 - Part B) which tells to verify whether      The automorphism group $\text{Aut} (\mathbb Z/2 \times \mathbb Z/2)$ is abelian.   I don't understand which group is meant here by $\mathbb Z/2 \times \mathbb Z/2?$ Is it $\mathbb Z_2\oplus\mathbb Z_2?$

I'm currently working my way through Harvard's online abstract algebra lectures (if you're interested, you can find them ).  The lectures come complete with notes and homework problems.  Of course, since I don't actually go to Harvard, I can't hand in the homework assignments to find out if I'm doing them correctly.  So I've decided to try to crowd source the grading of my solutions.  I'll post individual questions as I finish them and wait for comments.  I would like to get critiques of not just my reasoning but the style of my write ups as well.  Also, any alternative approaches to the problem would be welcome.  I've looked for forums dedicated to these kinds of OCW courses but have not been able to find any.  This surprises me.  It seems like, with the advent of these free online educational resources, an online meeting place for those who take advantage of them would be a natural offshoot.  So this might be a bit of an experiment.  Unless I'm the 873rd person to post something like this here.  If that's the case, sorry for being so long winded.  Anyway, on with the question.  This one is assigned in the 4th lecture.     Let $V$ denote the Klein 4-group.  Show that $\operatorname{Aut}(V)$ is isomorphic to $S_3$.   (I've moved my solution below to keep this question from showing up in the unanswered list.)  Thanks...


I have windows 7 and my password is numeric. When I start windows I always try to enter password with numpad and when it fails I see numlock is off. How should I change this behavior in windows?  I want the default keyboard options always to be "on for Numlock" and "off for Capslock and Scrolllock at my windows startup.

I'm using a PIN code to log on my computer. However, Num ⇩ is always turned off, even if on before shutting down my computer. This is quite annoying as I always have to retype my PIN.  I've tried the suggestions  (same as ). But with no result. If I don't enable num lock on log in screen and use the numbers above the normal keys, num lock turns on after log on. Then it's too late, unfortunately.  So, how can I make num lock enabled by default when logging in? Thanks.  Edit: While I still want to solve this, I've figured it is not such a big problem. I will need to press some key for the "enter PIN screen" to show, and using Num ⇩ works and enables num lock. But then, still annoying if the computer was only locked (with num lock on) and I turn it off, hehe.


An error occurred.   Starting /media/milo/DATA1/Milo/C++/build-test-Desktop-Debug/test... Cannot execute '/media/milo/DATA1/Milo/C++/build-test-Desktop-Debug/test':  Permission denied /media/milo/DATA1/Milo/C++/build-test-Desktop-Debug/test exited with code -1   below is the mount information  /dev/sdc5 on / type ext4 (rw,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/cgroup type tmpfs (rw) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755) none on /sys/fs/pstore type pstore (rw) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) systemd on /sys/fs/cgroup/systemd type cgroup (rw,noexec,nosuid,nodev,none,name=systemd) gvfsd-fuse on /run/user/1000/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=milo)   Can any1 tell me what's wrong? Thanks

I have a script that I need to execute on an NTFS partition. The script's permission is set to 600.  I attempted to modify the permissions by running chmod 755 script.sh, which doesn't report a failure or anything - but it also doesn't change the permissions on the file:  $ stat script.sh    File: `script.sh'   Size: 297070      Blocks: 584        IO Block: 4096   regular file Device: 811h/2065d  Inode: 35515       Links: 1 Access: (0600/-rw-------)  Uid: ( 1000/  xxxxxx)   Gid: ( 1000/  xxxxxx) Access: 2010-09-30 14:05:16.041621000 -0700 Modify: 2010-09-30 14:05:05.070157000 -0700 Change: 2010-09-30 14:05:05.070475000 -0700  $ chmod 755 script.sh $ stat script.sh    File: `script.sh'   Size: 297070      Blocks: 584        IO Block: 4096   regular file Device: 811h/2065d  Inode: 35515       Links: 1 Access: (0600/-rw-------)  Uid: ( 1000/  xxxxxx)   Gid: ( 1000/  xxxxxx) Access: 2010-09-30 14:05:16.041621000 -0700 Modify: 2010-09-30 14:05:05.070157000 -0700 Change: 2010-09-30 14:05:05.070475000 -0700   As you can see, it remains unchanged.


Since the official chromium-browser switched to relying on the -packaged variety, the browser gets "Permission Denied" when attempting to read any directory mounted after boot. For example, attempting to read the contents of a Kubuntu Live CD gives an error like:     Could not read the contents of kubuntu-20.04-live      Error opening directory '/media/travis/kubuntu-20.04-live': Permission denied   This happens for any volume which is not mounted at boot time (I haven't tested every possibility here, but seems to hold true). To grab a few examples, here's a clip from mount:  $> mount ... proc on /proc type proc (rw,nosuid,nodev,noexec,relatime) /dev/nvme0n1p2 on / type ext4 (rw,relatime,errors=remount-ro) /dev/sdc2 on /media/travis/kubuntu-20.04-live type iso9660 (ro,nosuid,nodev,relatime,nojoliet,check=s,map=n,blocksize=2048,uid=1000,gid=1000,dmode=500,fmode=400,uhelper=udisks2) media-server:/volumes/shared on /mnt/media-shared type nfs4 (rw,nosuid,nodev,noexec,noatime,vers=4.1,rsize=131072,wsize=131072,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.1.109,local_lock=none,addr=192.168.1.23,user=travis) ...    /proc: OK /: OK /home/travis: OK /media/travis/kubuntu-20.04-live: can not read /mnt/media-shared: can not read   I'm guessing this has to do with mount namespaces, so here's lsns:  $> lsns --type mnt         NS TYPE NPROCS   PID USER   COMMAND 4026531840 mnt      77  1616 travis /lib/systemd/systemd --user 4026533212 mnt      13  9697 travis /snap/chromium/1043/usr/lib/chromium-browser/chrome --no-default-browser-check --no-first-run --password-store   If I use nsenter to read from the volumes as I think Chromium should see it, things appear to work just fine:  $> sudo nsenter --target 9697 --mount -- ls -al /media/travis total 12 drwxr-x---+ 3 root   root   4096 Mar 22 09:24 . drwxr-xr-x  3 root   root   4096 Apr 16  2019 .. dr-xr-xr-x  9 travis travis 4096 Mar 16  2020 kubuntu-20.04-live   $> sudo nsenter --target 9697 --mount -- ls -al /media/travis/kubuntu-20.04-live total 964 dr-xr-xr-x  9 travis travis   4096 Mar 16  2020 . drwxr-x---+ 3 root   root     4096 Mar 22 09:24 .. -r--r--r--  1 travis travis    351 Mar 15  2020 .treeinfo ...   The browser, however, stubbornly refuses to list the contents of these directories if I attempt to choose a download location or pick a file to upload. What gives?    As a point of clarification: I am not installing Chromium through Snap directly, but using the official Ubuntu  package installed with apt install chromium-browswer. The /usr/bin/chromium-browser found there is just a shell script that calls /snap/bin/chromium. The package has a preinst script that calls snap install chromium, so you are downloading Chromium from Snap even when you don't want to.

I just upgraded to Ubuntu 19.10 and to my horror I discovered that the default browser Chromium can no longer access other partitions than /home.  This means that my partitions containing music and videos (/multimedia) for instance are no longer accessible e.g. to upload into Google Drive. This includes USB partitions.   I found another description of this phenomenon here:  where it says  "Also, while we acknowledge that most users will only need to access their home folders, it’s worthy to mention that you no longer can access system files & folders from inside Chromium (You can’t access anything except your home folder). This means that if you are to upload a file or an image for example into the Internet using an uploading website, then this file/image must be in your home folder, as you can not access directories such as /usr, /etc or other directories located in your root partition. In fact, you no longer can access any other partition at all, this includes USB sticks and other booted partitions:"  I wonder why this behaviour been introduced? it violates the whole idea of multiple disks, partitions and symlinks. Btw, this still works for Firefox.  My questions are   Are there any plans to fix this? I expect one reason for this behaviour is about security. If so, is it possible to explain why and how that makes for better security? The files on other partitions are legitimately accessible by the user anyway e.g. through symlinks. But with this change, I'll have to move them to /home before uploading so still accessing them although more slowly and cumbersome.  If this behaviour is now permanent, the question is how should we incorporate multiple disks in our filesystem?  Alternatively, can someone tell me how to find and install the debian package. I haven't been able to locate it?   This is not a duplicate of  because that is about a specific error during installation that I didn't get. My question is about the access chromium has in Ubuntu 19.10.  Anyway, I solved the problem via the following command by using the original debian package from Google:  sudo apt-get install google-chrome-stable   After that I can now access my other partitions again. I know this is hacky in the sense that the package isn't native to Ubuntu so I would really like to get some advice on how to incorporate multiple disks and partitions with this new restricted behaviour of Chromium.  Thank you very much


I have removed the chatter fields by using " feed tracking" option but i want to remove the chatter feeds based on the page layout (feed should be present for one layout , should not be present for another layout) . Is it possible in salesforce ?  I just cloned an existing layout and didnt check the "Enable feed" check box . But still i am able to see the feed

I need to display Case object(Detail page) in Portal Page for External users, And i need to Hide the Feed(No More "Show feed / Hide feed ") completely. Is it possible to hide feed in case object rather than creating a new page that display Case details in Portal page. i have created a new page layout with Un-checking "Feed based Layout" but i didnt achieved.Please any one clarify me,


i write some code which return two output the error appears,what is the main problem of my code???????  from urllib.request import urlopen as uReq from bs4 import BeautifulSoup as soup import os import sys import unicodecsv as csv import codecs from urllib.request import urlopen   for i in range(22):      my_url = "https://www.bamilo.com/electronic_accessories/?source=gfm/?facet_is_mpg_child=0&viewType=gridView&page="      uClient = uReq(my_url + str(i))      page_html = uClient.read()      uClient.close()      page_soup = soup(page_html, "html.parser")      containers = page_soup.findAll("div" , {"class" : "sku -gallery" })      filename = "product.csv"     f = codecs.open(filename, "a" , "utf-8-sig")     headers = "price_two\n"     f.write(headers)       for container in containers:          price_old = container.findAll("span",{"class" : "price -old "} )          price_two = price_old[0].text.strip()          print("price_two " + price_two)          f.write(price_two.replace(",", "")  + "\n")  f.close()   ERORR :::  > price_two 1,800,000ریال price_two 2,800,000ریال Traceback (most recent call last):   File "F:\bam.py", line 34, in <module>     price_two = price_old[0].text.strip() IndexError: list index out of range

How do I access the index in a for loop like the following?  ints = [8, 23, 45, 12, 78] for i in ints:     print('item #{} = {}'.format(???, i))   I want to get this output:  item #1 = 8 item #2 = 23 item #3 = 45 item #4 = 12 item #5 = 78   When I loop through it using a for loop, how do I access the loop index, from 1 to 5 in this case?


How do I compute the increase when the old value is zero? I know that usually we compute it as $$ \frac{N-V}{V} \times 100, $$ where $N$ is the new value and $V$ is the old value.  So,   going from $50$ to $500$, the increase is $900\% = \frac{500-50}{50} \times 100$ going from $50$ to $75$, the increase is $50\% = \frac{100-50}{50} \times 100$   But when going zero to $X$, where $X$ is any value greater than zero, the increase is $100\%$? (In this formula you can't divide by zero).

This is a very simple maths problem, which doesn’t seems simple to me when I just put some extra thoughts on it. So need to borrow some extra brains for this.   Question: If cost of coffee in my office was Dollar 0 till yesterday and today it is Dollar 2.5 then what is the percentage increase in the cost of coffee?  Initially it seemed like 2.5% increase, simply by distributing number from 0 to 100, but this is not the case.   Some suggested it is infinitely more than the previous value, because we are calculating percentage by dividing by zero. But what about this if the cost of coffee was $0.25? Isn’t still infinitely more! Something is wrong here.   PS: Yes, coffee were free in our office but not anymore, and we are still recovering from this shocker. 😥


I and my friends are doing a maze minigame and there's a killer, when the killer is 1 block of distance from the other player (a survivor) the survivor is going to look at the killer, but the only problem is that I don't know how to do that, I made the command to detect when the player distance is less or equals one (..1) but yeah, idk how to make the player look at the killer, we use tags, and when the distance is ..1 it's not just gonna make the player face the killer but also, play a 10 second audio (Slender death sound) and in that time everyone is gonna have slowness (the killer and the player), please help!

If I have an entity, is it possible to teleport that player to face the entity without teleporting the player to the entity (Just changing his rotation)? How could I accomplish this?


i am trying to sort a file that has 600 columns. i want it gives me highest number number in all on top (descending order for each field) i just slice the file which is space separated to see if it is working fine. i tried out these commands but  seems as if i am doing something wrong  $ cat test.txt +0.07273 +0.67860 -6.99580 -0.44278  -7.21295 +0.19793  $ sort -nr test.txt # (just sorted column one) -7.21295 +0.19793 -6.99580 -0.44278  +0.07273 +0.67860  $ sort -k1,1nr -k2,2nr test.txt # (just sorted column one) +0.0727  +0.67860 -6.99580 -0.44278  -7.21295 +0.19793   how can i sort entire columns in descending order. it will be hard to use k 600 times

I am aware that it is possible to sort primarily by one field and secondarily by another field. For example:   $ echo -e "1 5\n1 4\n8 2\n1 9" | sort -k 1,1n -k 2,2n 1 4 1 5 1 9 8 2 $    However, am I correct that sort always keeps the lines intact, e.g. it is not possible to sort in a way that output would be following:  1 2 1 4 1 5 8 9   If this is not possible with sort, then what would be the correct tool for this?


Consider the equation, $x^a = a^x$.  If a is of the form $1.6 + 0.4k$, where $k$ is a natural number, then the equation has $3$ solutions. I checked them until $k = 1000$, but was unable to find a reason for this. Is there any plausible explanation for this? If yes, what is it? if not, why?  The possible duplicate question doesn't explain why there are 3 solutions for this particular form!  Thanks, John.

I note from the archive discussion of the case for integers, which I'm fine with.   For the positive reals, I have set up axes for x, y and z = x ^ y. The solution set is then graphed by a space curve in the surface, necessarily symmetrical about the plane y = x. I need the equation of the orthogonal projection of this curve onto the x-y plane. (All I have shown so far is that  $x ^ y > y ^ x$ in the region right of the line y = e and above the line y = x.)


Thanks to this site, my app is coming along nicely. However, it crashes when switching to a new activity I just created. There are 6 activities where the user answers questions, on Activity #5 in the sequence, the app crashes when I press the continue button. I get the standard "Unfortunately, App has stopped." When I press OK, the app closes and re-opens, and I am taken back to Activity #4, which retains the user input which I saved to SharedPreferences.  Log from the time I press the continue button:  02-27 08:42:54.231 7307-7307/com.health.hermes D/ViewRootImpl: MSG_RESIZED: ci=Rect(0, 96 - 0, 0) vi=Rect(0, 96 - 0, 0) or=1 02-27 08:42:54.541 7307-7307/com.health.hermes D/ViewRootImpl: ViewPostImeInputStage processPointer 0 02-27 08:42:54.611 7307-7307/com.health.hermes D/ViewRootImpl: ViewPostImeInputStage processPointer 1 02-27 08:42:54.621 7307-7307/com.health.hermes I/Timeline: Timeline: Activity_launch_request id:com.health.hermes time:1000022770 02-27 08:42:54.681 7307-7307/com.health.hermes D/TextView: setTypeface with style : 0 02-27 08:42:54.681 7307-7307/com.health.hermes D/TextView: setTypeface with style : 0 02-27 08:42:54.691 7307-7307/com.health.hermes D/AndroidRuntime: Shutting down VM 02-27 08:42:54.691 7307-7307/com.health.hermes E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.health.hermes, PID: 7307     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.health.hermes/com.health.hermes.KiPercentActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setFilters(android.text.InputFilter[])' on a null object reference         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253)         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)         at android.app.ActivityThread.access$1100(ActivityThread.java:221)         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)         at android.os.Handler.dispatchMessage(Handler.java:102)         at android.os.Looper.loop(Looper.java:158)         at android.app.ActivityThread.main(ActivityThread.java:7225)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)      Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setFilters(android.text.InputFilter[])' on a null object reference         at com.health.hermes.KiPercentActivity.onCreate(KiPercentActivity.java:30)         at android.app.Activity.performCreate(Activity.java:6876)         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)          at android.app.ActivityThread.access$1100(ActivityThread.java:221)          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)          at android.os.Handler.dispatchMessage(Handler.java:102)          at android.os.Looper.loop(Looper.java:158)          at android.app.ActivityThread.main(ActivityThread.java:7225)          at java.lang.reflect.Method.invoke(Native Method)          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)    If you see the cause, kindly point out how I can better understand the logcat so I can start diagnosing myself. Thank you!

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'm trying to use black fin 533, to create a delay of 1ms using one of its timers, I read the datasheet but I can't understand how to set a 1ms delay. here is the datasheet   Please I need clarification of timer width and timer period.

I have been in Embedded system for 8 months. I have worked application part more compare with low level. I have basic questions on systems ticks,   How to calculate the system tick of Timer, if I am starting the Hardware Timer of a controller for generating any delay. If I am having the 16-bit timer for example and I configured the system clock for 8MHz. As per my knowledge the single tick will be T=1/f. Then one single tick will take 0.125 microsecond. Is this correct? or any other dependency to calculate it. Whether this calculation will vary with controller by controller? Is there any way to configure the clock(eg 1MHz) for only Timer or any other peripheral with out changing the System Clock(eg 8Mhz)   If controller goes to low power mode(typically a changing of power mode). The timer resolution will also change? whether I need to change the setting of Timer for each power Mode.


I have a  in play. I then play . If my opponent's permanent I gain control of is a creature, does this creature also receive the counter from Cathar's Crusade?

I had several humans on the battlefield.  On turn three, I played . On turn four, I played . On turn five, during my upkeep, this question came up.  At this point, I need to draw/reveal three cards. If I reveal a human, Descendants' Path will allow me to cast it without paying its mana cost.  So, does it matter when I draw the human?  The static abilities state "at the beginning up your upkeep..." which leads me to believe that those two draws/reveals would happen before my normal draw. If that's the case, does the draw order happen in the same order that I played the enchantments?  In the end, that's how we decided to do it. I drew first for Triumph of Ferocity, then I revealed for Descendants' Path, then I drew for my turn. Did we do it right?


My question and context with explanation are given below. Thank you in advance.   Faraday’s Law () states that a time-changing magnetic field vector induces a curl of the Electric field around that point. However it does not specify how quickly the necessary spatial gradient is developed in the Electric Field to satisfy that curl. Of course, the Electric Field vectors around that point cannot just jump to the required values instantaneously in accompaniment as soon as the magnetic field starts changing at a fixed rate, since it is required that the Electric Field has a sensible rate of change to in turn induce a curl of the magnetic Field and continue the propagation of the wave. It would seem the exact rates at which the Electric and Magnetic Fields are changing is critical in the mechanism of an EM wave’s propagation. How would I then calculate the rate of change of E somewhere along the wave given I know the rate of change of the B vector that began it, and given the wave is restricted to one dimension for simplicity? There should after all be some delay in how the EM wave moves from point to point in space, seeing as it moves at the finite speed of causality (3*10^8 m/s), as shown in the first image:    Some of my ideas so far have been that perhaps the rate of change of E is determined such that it exactly cancels the growth of the time-changing E vector that gave rise to a curl of B before, which developed at such a rate to induce a curl of E, which demands this rate of change of E which I am talking about now. In this way the wave might level out the growth of the fields in its wake and spread the change further outwards, in the same way smoothening out a crease spreads it elsewhere. However I am stuck on how to show this rigorously.  I am open to any difficulty of maths, so long as the answer provides the explanation. Below are some diagrams to help visualize what I am talking about:    Faraday's Law requires that a curl of E is developed, which under these restrictions requires a spatial gradient of E to appear across that point. Since the field across that point was previously in some other state, it is required that the Electric Field vectors that are infinitesimally close to that point undergo a rate of change through time to achieve the desired state of curl. The question is, how quickly is this desired state of curl achieved?


I have executed this dumb code for some testing: int main(){      char a[4];     a[3000] = '2';  //no problem     sleep(30);     printf("wake up\n");     a[20000] = '2'; //segmentation fault     printf("No segmentation fault!\n");     while(1);  }  I know that this is so dumb (creating a 4 bytes array and wanting to store at the position 3000 and at the position 20000) but, as I said, it's only for testing. What I wanted to test is if accessing to a page reserved for stack space will result in a Segmentation Fault. It shouldn't, but it did! How I know that the page that belongs to the a[20000] is a reserved page for this process? Well, during the sleep(30) time I watched the content of /proc/pid/maps and I got this: 7ffdce868000-7ffdce889000      rw-p 00000000 00:00 0                          [stack]  If you look at starting and finishing directions of the stack, you will see that an access to a[20000] is covered by this directions, since OS has assigned for that moment 33 pages of stack (which is 135168 Bytes). On those pages the process has reading and writing permision. So, why did I got segmentation fault??

I am preparing some training materials in C and I want my examples to fit the typical stack model.  What direction does a C stack grow in Linux, Windows, Mac OSX (PPC and x86), Solaris, and most recent Unixes?


Is this question correct? What is the chronological order of John as the president of our country?

I am the third daughter (or son) of my parents.   OR      How should a question that is answered with the above sentences be framed?


My gas water heater, continuously lets hot water out from the outlet (seems it is connected to tp valve, it goes through the wall to outside the home).   If I turn the water heater to low (much below the normal setting with the recommended arrow), it stops after a few minutes.   What could be the problem and I am worried if this is something dangerous, in addition to wastage of water and gas..?  Also, I noticed that my heater is making more noise than ever..It is a 3-4 years old heater..

A few days ago I noticed about a capful of water in the pail at the bottom of my water heater's TPR valve outlet.  This is the first time I've had any water come out of the TPR when I wasn't testing it.  I moved into this house in 2011.  In 2012 I installed a water expansion tank, with a ball valve to disconnect the hot water system—the expansion tank plus water heater.  I realize the water expansion tank is probably near the end of its life.  The water heater is electric and over 20 years old (I know), but I've been flushing it thoroughly once a year and replacing sacrificial anodes as needed, and it hasn't leaked yet.  The only recent change to the system is that I used to have a pressure gauge connected to a hot water faucet instead of the normal connection to my washing machine, and I finally removed the gauge and reconnected the hot water hose for the washing machine.  When the washing machine runs, I can hear a knock in the pipes when the washer hot water valve turns on or off (which was why I installed an expansion tank in the first place).  Note that there is a PRV on the water main.  To test things, I opened the TRP valve and closed it against.  It took its good old time closing and kept leaking for a while.  So I opened and closed it again, and that time it closed more quickly and stopped leaking.  I had seen this once before in testing, so I didn't read anything into it.  Then I closed the ball valve to remove external pressure from the hot water system, I opened all of the hot water faucets above it, and I checked the air pressure inside my expansion tank.  It's down around 28 PSI from the 60 PSI that it's supposed to be at, so I'll have to address that.  But when I opened the ball valve again and individually closed each faucet, the TPR valve spit out a bit of water again when I closed the last valve.  Am I correct in my assumption that the TPR valve is failing?  Is it normal for them to fail gradually instead of opening catastrophically?  Would the underpressured expansion tank have any bearing on this?


I have been playing around with the Onboard settings and even though I select the option "Show when unlocking the screen" from the settings the keyboard still doesn't appear when on screen lock. This appears to be an issue with Onboard and Ubuntu. Which is frustrating for me because I really like Ubuntu on my tablet but that is an important feature that doesn't seem to be working right and is holding it back.  I see there is another question pertaining to this exact same issue which hasn't received a response. So I am asking again, has anyone gotten this working? Any word from the developers (I can't seem to find any) on making this functionality available?

I have a laptop-tablet device and I'm trying to enable onboard on the lock-screen.  Enabling onboard on the login screen is no problem but enabling the option  Show when unlocking the screen   is not giving the desired effect i.e. showing the keyboard on the lock-screen, when you lock your screen in a session.  Several questions exist that asks how to enable onboard on the lock-screen, however I have yet to find any that are actually referring to the lock-screen and not the login screen.  Is there any way to enable onboard on the lock-screen?  Edit:  This same question looks to be adressed here:  , however the options presented here do not give me an on screen keyboard on the lock-screen.


Calendar rightNow = Calendar.getInstance(); String month = String.valueOf(rightNow.get(Calendar.MONTH));   After the execution of the above snippet, month gets a value of 10 instead of 11. How come?

In java.util.Calendar, January is defined as month 0, not month 1. Is there any specific reason to that ?  I have seen many people getting confused about that...


I'm doing some provisioning work, and it happens that I now need to do something I've never done before that I'm completely stumped on how to do.  I need to be able to generate an ssh key pair (ssh-keygen -t rsa) on one system, let's call it System A, and then transfer that pair to System B & System C in such a way that I can ssh from System B to System C. In other words I need an ssh key pair where I don't actually have to generate the key on any of the systems that will be ssh-ing.  How do I do this?

I need to use another computer to access my ssh server. This is because a recently implemented vpn at my university doesn't work on my current computer and I have lost access to the server.   I ssh via encrypted ssh keys. Can I copy these keys to the new computer (on which the vpn works). I tried copying the id_rsa and id_rsa.pub files in the ~/.ssh folder but it doesn't recognize the keys and there is no prompt to input a password to decrypt the keys.   EDIT: I can't access the server to generate a new key pair for the new computer and am out of the country so can't physically access it.   Thanks.


In the bottom of the screen I cant see my layers anymore. I switch to all local, global,etc but I can't find the layer menu. When I press M to move my object I get a message: Move from localview  How can I get the layer menu back?

For some reason the layer selection and the Lock to Scene button disappeared in 3D View / Object Mode. I can't find an option to toggle the visibility.  As it is supposed to look like   How it currently looks like    File / New restores the visibility therefore it must be a setting within the .blend file. How can the layer selection be restored?


I let a camera follow a round path which also tracks an empty (see reference). There is no problem in animating this, however I want the camera to start moving slowly and generate more speed and also to come to a halt slowly (ease in & out). But when I take a look in the graph editor there is no curve to edit.      Edit:  Also if I choose the curve there is no graph to adjust.

I'm modeling a car driving along a road(speeds up, slows down, and stops at traffic lights to wait till the lights turn green, etc.) What is the best way to animate the camera path for the following scenario?   The camera starts moving from point A, and it takes 500 frames to get to point B. During this 500 frames, the camera first gradually speeds up, then moves at a constant speed, and finally slows down to a complete stop at point B. The next 50 frames, the camera will stay at point B. From frame 551, it takes another 500 frames to get to point C from point B. The camera experiences the same motion as described in #1 (speeds up, constant speed, slows down, then stop.) Again, the camera will stay at point C for another 50 frames.  Point C to D is a curve path ( added using Shift + A -> add path). I want the camera to move along the path from frame 1101 to frame 1200. The camera should have the same motion as before(speeds up, constant speed, slows down, then stop.)   What is the best way to animate the camera path in this case? Is there any Python scripts available and can be applied to case like this? Thank you all in advance for your replies.


How can I give my datamember date from the type Date a value? I added in my class the import java.util.* statement but I can't find a way to give it a value. It isn't a string like "12-11-2014" This is one of my first project with Java, so I don't have many experience. ;-)  Greetings Moleculation  import java.util.*;  public class Training { // data members (instance variables) private double distance;  // in km private double time;  // in seconden private String type; private Adres address; private Date date;   public Training(int distance, int time, String type, Adres address, Date date) {     // initialise data members (if necessary)     this.distance = distance;     this.time = time;     this.type = type;     this.address = address;     this.date = date; } // getters public double getDistance() {     return distance; } public double getTime() {     return time; } public String getType() {     return type; } public Date getDate() {     return date; } public Adres getAddress() {     return address; }  // setters  }

I have a String representation of a date that I need to create a Date or Calendar object from. I've looked through Date and Calendar APIs but haven't found anything that can do this other than creating my own ugly parse method. I know there must be a way, does anyone know of a solution?


I'm ditching Windows 10 once and for all and I was wondering if my oldish desktop can rock and roll with Ubuntu 18.04!? The PC configuration is as follows:  8GB RAM (DDR3), Nvidia GeForce GTX 650, SSD 120 GB. I read that Ubuntu 18.04 comes with Gnome 3 which is a resource hungry DE.

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


How can I 'flatten' Alt+Tab cycle to show all application windows?    For example, before this update, you would just continue Alt tabbing until you reached the required application window. However, if I have  windows of an app, I have to get to it with Alt+Tab, press arrow down key and then choose between instances.  Is it possible to configure alt-tabbing so that it skips that extra 'arrow down' step? Is it possible without 3rd party app?

Currently if I hold ALT + TAB and then while still holding down ALT I press TAB I am able to go between applications in a little view and then when I release all the keys that application and all its windows come to the front.  And this is very useful, but I would like to know if there is a way of switching between individual windows with this keyboard shortcut in the same way rather than grouping windows with an application to switch to?  I am running Ubuntu GNOME 15.10 with GNOME 3.18.


If $F_n$ is the $n$-th fibonacci number, then prove that, $$F_n={n-1 \choose 0 }+{n-2 \choose 1 }+{n-3 \choose 2 }+\ldots$$  I tried the idea of using Pascal's triangle, but it seems to need some adjustment, so I am stuck, please help.    Any combinatorial argument would be of greater help than rigorous proof.  Thank you.

The binomial sum   $$s_n=\binom{n+1}{0}+\binom{n}{1}+\binom{n-1}{2}+\cdots$$   satisfies the Fibonacci relation.   I failed to prove that $\binom{n-k+1}{k}=\binom{n-k}{k}+\binom{n-k-1}{k}$... Any hints or suggestions?


When I try to rename one of these Quick access shortcuts,...    , the original folder name are renamed also.  What I'm looking for is to rename the shortcuts without renaming the original folders names.  OS: Windows 10    This question isn't a duplicate of . This question is asking about how not to rename the original folder with the same name of its Quick Access shortcut on being renamed, while the other question is asking about the existence of the rename feature itself — not its relation with the original folder name.

I just got done upgrading Windows 8 to Windows 10 and I've found that the 'Favorites' panel in Windows Explorer got replaced with a 'Quick Access' panel and I can't seem to find a way to rename the pinned items in Quick Access like I could for favorite items under Windows 8.  Some of my pinned items are program-generated folders and I really don't have the option to rename them.  Am I missing something or did the rename feature get left out?


I'd like to extend my supply of yeast (It's hard to get right now). My wife does not enjoy the taste of sourdough, so I was wondering it it's possible to create a self-replenishing culture, starting with store-bought, active dry yeast we already have on hand?

Like many people sheltering-at-home, I'm baking . My yeast supply is running low, and I'm not sure I'll be able to get more on demand. I'd like a simple way to make sure I have yeast on hand for my next batch. Could you all recommend a method for storing a starter culture?  Specifically:   How should I store it (how much? where? I have a fridge ~4C and a wine cooler ~13C)  How often should I feed it? With what? Should I divide the culture when feeding?  How much should I use when baking? Can I treat it like dry active yeast, or does it need more/less time?   For some other context, I'm a novice at making bread (I've made it a few times, and others in my family make it more often). I see lots of advice on sourdough starters, but am interested in something that's a replacement for dry active yeast (unless sourdough starters are actually easier to maintain). I found a  that was similar, but it focused on long-term storage of yeast and the answers did not describe how to use the starter.  Your advice is appreciated.


As the question stated, what is the remainder when ${13}^7$ is divided by 9? There are quite a few online questions similar to this. However, I do not really understand the concept of it.  I have attempted this question by looking for a pattern (as suggested in some online search):  ${13}^1 / 9$ = 4 remainder  ${13}^2 / 9$ = 7 remainder  ${13}^3 / 9$ = 1 remainder  ${13}^4 / 9$ = 4 remainder  ...  There is clearly a pattern of 4, 7, 1 before it repeats itself in the power 4. For power 7, the remainder is therefore 4. I believe the answer to this question is 4 remainder.  My question is how will I approach if the power is much larger than power 7? Say, if we have ${13}^{100}$ divide by 9, is it right to find the remainder using this method:  $100 / 3 = 33.33333 $  Since $33 * 3 = 99$, for the remainder at the 100th power, it will be 4.  Is there a more elegant way of doing this?   Edit:  Actually, this method does not seem to work if the divisible value is larger than 13. Any idea?

I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two:   $13^{100} \bmod 7$ $7^{100} \bmod 13$   I've also heard of this formula:  $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$  But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?)  Any hints or pointers in the right direction would be great.


I have a question from my Stats Homework that is worded as follows:  Based on a random sample size n from the Beta(a,2), construct the MLE of a   I really don't know how to go about solving this, as the beta function in the pmf of the beta distribution is throwing me off. I would appreciate any input and guidance.

I'm taking a Mathematical Statistics course and trying to work through a homework problem that reads:  Let Y1, ..., Yn be a random sample from a Beta(1,$\theta$) population.  Derive the MLE for $\theta$.  Getting started, I set up the likelihood function as:  $$ L(\theta) = \frac{\Gamma(1+\theta)}{\Gamma(1)\Gamma(\theta)}\prod_{i=1}^n(1-Y_i)^{\theta-1} $$  This simplifies to:  $$ L(\theta) = \theta(1-Y_i)^{n(\theta-1)} $$  Taking the log:  $$ l(L) = log(\theta) + n(\theta-1)log(1-Y_i) $$  Take the derivative:  $$ \frac{dl}{d\theta} = \frac{1}{\theta}+nlog(1-Y_i) $$  Solve for $\theta$:  $$ \theta = \frac{-1}{nlog(1-Y_i)} $$  But this can't be right as I've not dealt with the summation of $Y_i$.  In most examples I've seen, this goes away as a result of the summation being divided by n,b ut in this case I can't find where I've gone wrong.   I appreciate any tips.


I put some balls (denser than water) in a bucket. I took a stirring rod, and swirled the water in one direction. The water became low in the middle, and high along the edges (centrifugal force). But the balls at the bottom clustered in the middle. Even when I tried to dislodge them with the stirrer, they would quickly return to the center.  Why did they not go out to the edge of the bucket, especially since they are denser?

At xmas, I had a cup of tea with some debris at the bottom from the leaves.  With less than an inch of tea left, I'd shake the cup to get a little vortex going, then stop shaking and watch it spin.  At first, the particles were dispersed fairly evenly throughout the liquid, but as time went on (and the vortex slowed, although I don't know if it's relevant) the particles would collect in the middle, until, by the time the liquid appeared to almost no longer be turning, all the little bits were collected in this nice neat pile in the center.  What's the physical explanation of the accumulation of particles in the middle?  My guess is that it's something to do with a larger radius costing the particles more work through friction...


Have I just forgotten the obvious, or is the "manual" comparer the best way to go?  Basically, I just want to compare the contents of type (small) byte-arrays. If all bytes match, the result should be true, otherwise false.  I was expecting to find that Array.Equals or Buffer.Equals would help.  Demonstration Code:    var a = new byte[]{1, 2, 3, 4, 5};   var b = new byte[]{1, 2, 3, 4, 5};   Console.WriteLine(string.Format("== : {0}", (a == b)));   Console.WriteLine(string.Format("Equals : {0}", a.Equals(b)));   Console.WriteLine(string.Format("Buffer.Equals : {0}", Buffer.Equals(a, b)));   Console.WriteLine(string.Format("Array.Equals = {0}", Array.Equals(a, b)));   Console.WriteLine(string.Format("Manual_ArrayComparer = {0}", ArrayContentsEquals(a, b)));   Manual function:  /// <summary>Returns true if all elements of both byte-arrays are identical</summary> public static bool ArrayContentsEquals(byte[] a, byte[] b, int length_to_compare = int.MaxValue) {   if (a == null || b == null) return false;   if (Math.Min(a.Length, length_to_compare) != Math.Min(b.Length, length_to_compare)) return false;   length_to_compare = Math.Min(a.Length, length_to_compare);   for (int i = 0; i < length_to_compare; i++) if (a[i] != b[i]) return false;   return true; }

How can I do this fast?  Sure I can do this:  static bool ByteArrayCompare(byte[] a1, byte[] a2) {     if (a1.Length != a2.Length)         return false;      for (int i=0; i<a1.Length; i++)         if (a1[i]!=a2[i])             return false;      return true; }   But I'm looking for either a  function or some highly optimized proven way to do this.  java.util.Arrays.equals((sbyte[])(Array)a1, (sbyte[])(Array)a2);   works nicely, but it doesn't look like that would work for x64.  Note my super-fast answer .


Will my troops being researched in the laboratory keep going if I upgrade my laboratory? Or will they stop?

While playing Clash of Clans, I am upgrading my lightning spell then decided to upgrade my laboratory, then I did. What will happen to the lightning spell I am upgrading? I assume it is still upgrading cause they don't refund my elixir.


how can I print difference line number and column number for tab separated files in linux  example- compare File 1 vs File2 and print line no. for difference record and column no of difference present in file2.  In file1:  User_ID   First_name    Last_name   Address                     Postal_code   User_1    fistname      Lastname    35, Park Lake, California           32068  user2     Johnny        Depp        32, Park Lake, California             user3     Tom           Cruise      5322 Otter Lane Middleberge         32907  user4     Leonardo      DiCaprio    Half-Way Pond, Georgetown           1230  user5   Sylvester       Stallone    6762,33 Ave N,St. Petersburg        33710   and  In file2:  User_ID   First_name    Last_name   Address                     Postal_code   User_1    fistname      Lastname    35, Park Lake, California           32068  user2     Johnny        Depp        32, NEW Street, California          96206  user30    Tom           Cruise      5322 Otter Lane Middleberge         32907  user4     Leonardo      DiCaprio'   Half-Way Pond, Georgetown           00000  user5     Sylvester     Stallone    6762,33 Ave N,St. Petersburg        33710  user6     Nicolas           Cage                                        55010   expected result:- difference in file2 is for line number followed by column number-   3 COLUMN NO- 4,5  4 COLUMN NO-1   5 COLUMN NO 3,5  6 COLUNN NO 5  7 COLUMN NO 1,2,3,4,5   Note: File size to be compare is in GB and File is tab separated and has more than 400 tab separated column.  Currently I am using Awk command for printing the line number but i am not able to get column no.  Can we loop the awk or have nested awk   Current command using-  awk 'NR==FNR{Arr[$0]++;next}!($0 in Arr){print FNR}' file1 file2

how can I print difference line number ignoring 1st column for tab separeated files?  example- compare File 1 vs File2 by ignoring 1st column and print line no. for differnce record present in file 2.  In file1:  user1   fistname    Lastnamename user2   Johnny            Depp user3   Tom               Cruise user4   Leonardo          DiCaprio user5   Sylvester         Stallone   and  In file2:  user10   fistname    Lastnamename user2   Johnny            Depp user30  Tom'               Cruise user4   Nicolas           Cage user50  Sylvester         Stallone   expected result:-     difference in file2 is for line number 3,4  Note file size to be compare is in GB and File is tab separated


I need a bit of help with this.      She is a photographer but that camera is her brother's-in-law     or:        She is a photographer but that camera is her brother-in-law's   I am aware that I could change the construction to make things easier, like:      She is a photographer but that camera belongs to her brother-in-law       However, I would really like to find out what's the correct way to write the sentence.

1) My brother's friend's opinions      2) My brothers' friend's opinions   I hope "1" and "2" are pretty clear and correct.  Now, let us suppose that the brother in "1" is a brother-in-law and that all the brothers in "2" are brothers-in-law.  Question is: How do we rewrite "1" and "2" in these cases?  Following the J.R.'s suggestion, I have done some preliminary researches and I found that when in-laws become possessive brothers-in-law is written brother-in-law's. So, I would conclude that we should rewrite "1" and "2" in the same way, as follow.     i) My brother-in-law's friend's opinions.      ii) My brother-in-law's friend's opinions.   But, if it is so, how can we distinguish the two different cases?


Can I page-break automatically a large number of equations in the same subequation-environment? I have to put them in an appendix and I cannot continuously change where the align-groups begin and end. As a result, the appendix starts in a new page, and worse, sometimes also with one blank page before it.   The align groups seem unnatural, but I have to create them in order for page-break to take place. Could this be achieved automatically?  \documentclass[11.5pt,a4paper ]{amsart}  \usepackage{lipsum}  \usepackage{latexsym,amssymb,enumerate} \usepackage[english]{babel}  \begin{document}   \section{First Section} \lipsum[1] \lipsum[2]  \appendix \section{Long proof that nobody wants to read} \begin{subequations} \begin{align} \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long } &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber  \end{align}  \begin{align} \mbox{new block with a} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber  \mbox{new block with a} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber  \mbox{new block with a} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber \\ \mbox{long} &   \mbox{list}  \\ \mbox{of} & \mbox{equations} \nonumber \\ \mbox{which } & \mbox{I cannot suppress} \nonumber  \end{align}  \end{subequations}     \end{document}

I have a very long derivation, that needs to look like:     A = B \\ = C \\ = D \\   etc. The derivation spans across many lines. I'm looking for a way to typeset it so that when it reaches the end of the page it can continue naturally on the next page, without trying to fit the entire equation into a single page. I'm currently using eqnarray and it insists that all its contents sit on a single page.  Can anyone suggest another environment that supports multi-page equations?


I put a can of unopened pork n beans in fridge to get cold for next day and they were pushed to the back and fogoten. How long will they be ok to eat,?

How do I know if a given food or ingredient I have is still good, or if I should discard it?  How can I best preserve a food or ingredient?     This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.


If A² = I, prove that the matrix A is diagonalizable.  I have computed the eigenvalues to be 1 or -1 but I'm not sure how to proceed from here.   I'm thinking along the lines of "since rank(A + I) + rank(A - I) = n, therefore there exists n linearly independent vectors which corresponds to n eigenvectors. Hence, A is diagonalizable". Is that correct?  Thanks in advance!

Let $A$ be a square matrix of order $n$ such that $A^2 = I$.  Prove that if $1$ is the only eigenvalue of $A$, then $A = I$. Prove that $A$ is diagonalizable.   For  (1), I know that there are two eigenvalues which are $1$ and $-1$, how do I go about proving what the question asks me?


I am totally psyched by the rubber duck addition to Stack Exchange!   I eagerly clicked on it but it wants a microphone. I don't have one, so I clicked "no" and it tells me to explain the problem anyways (I get it, I get it, har har). This question is not about that.  The problem is that I can't get rid of this dialog. Clicking "yes" lets me dismiss the dialog by clicking elsewhere.  I'm on an iPad.

When I click the duck, she asks me if I have a microphone. I press "no" but she tried to listen anyway, asking me to speak up.  Curiously, the browser did NOT ask for microphone permission even when I said "yes".  Edit: Thank you guys, next time I will have my morning coffee before putting in discussion such magnificent piece of technology.


I understand that the reason for asking questions that solicit opinions or suggestions is to avoid subjective answers and that we want the questions here to be answerable by an objective and definite answer.  But what if I have defined a set of requirements and the question isn't about what's the best out there but rather what could satisfy a set of objective requirements? Isn't that enough to make the question legitimate enough to be asked here?

In a perfect world, the so-important advice "do not reinvent the wheel" would be extensively followed. In practice, everyday millions of wheels are reinvented simply because someone didn't know an existing solution for a specific problem. The best way to find a library, today, is googling it, but it's not always obvious which keywords to use. The lack of a tool for finding solutions is very counterproductive for the dev world as a whole. Stack Overflow is not very receptive for recommendation threads. So what about a new SE for it?


I'm new to Ubuntu and networking and I've got myself stuck. I have an budget NAS setup (raspberry pi running OMV with an SMB share). I have setup the share in Ubuntu by following  guide. I have permanently mounted the drive and can access all the files in the share. However, after connecting to a VPN (surfshark), following  guide I can no longer access the share. I get the following message "Could not display "share". The file is of unknown type". Setting up the VPN entailed editing /etc/fstab, and putting this: //my.nas.ip.address/media  /media/share  cifs  credentials=/home/user/.smbcredentials,iocharset=utf8  0  0  Would I need to change this to access the NAS? Also, when I run the VPN on my windows machine, I don't have any trouble accessing the NAS. edit: I should also mention that I'm running Ubuntu through a VM on the windows machine

I have configured open VPN in my home so that it can be accessible from my office easily.  Now I want to share samba via my open VPN. How can I share samba over open VPN between Ubuntu and Windows?  Home public IP: HHH.OOO.MMM.EEE Home desktop IP: 192.168.10.10 Office public IP: OOO:FFF:III:CCC Office Windows desktop IP: 192.168.1.10


After installing Ubuntu 14.04,I installed kubuntu-desktop so I can choose between unity and KDE. But now the kubutu logo appears when I turn on the computer. How can I restore the ubuntu logo (which appears when the computer is booting up)?

I am making a custom distribution, and have a question about the Ubuntu Logo with 5 dots displayed when booting up.  The Ubuntu-Logo-Script in the /lib/plymouth/themes/ubuntutext folder has the word Ubuntu and beneath that 5 progressing 'dots'. Is it possible to remove the progress bar dots, and instead replace it with a faded Ubuntu logo, that gradually colors up to full?


I'm trying to write integration test with Citrus framework and I keep getting NullPointerException on http() line.   And here is the stacktrace.     java.lang.NullPointerException       at com.consol.citrus.dsl.testng.TestNGCitrusTestDesigner.http(TestNGCitrusTestDesigner.java:438)       at com.test.tests.RestProviderIT.testGetUsers(RestAppIT.java:32)       at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)       at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)       at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)       at java.lang.reflect.Method.invoke(Unknown Source)   public class RestAppIT extends TestNGCitrusTestDesigner{  @Autowired private HttpClient restClient;  @Test @CitrusTest public void testGetUsers() {     http()         .client(restClient)         .send()         .get("/comp/users")         .accept(ContentType.APPLICATION_JSON.getMimeType());      http()     .client(restClient)     .receive()     .response(HttpStatus.OK)     .messageType(ContentType.APPLICATION_JSON.getMimeType()); } }   I have setup the endpointconfig class and defined the restClient there. Can you help me with this issue?

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 am doing a project by placing new text  in 20th century fox logo .I want to pause my on going blender project and then restart the same project. how do I do it?. the project is half done. now i want to pause it and restart it again later.

I would like to pause a render that I have started, with the intention of resuming it at a later time (but during the same Blender session).  How can I do this?


I have a data extension which has field names "links" and "Interest". Filed Links  contains HTML links to certain images which are hosted on our internal server.  I would like to create an email which will show the image for subscriber with interest A and show another image for subscriber with interest B.  Please let me know how can I achieve this (to show images in an email from data extension  links )

In Data Extension one field 'HTML' have Data that I have shown below, Now I have to Find the 'Href', and and at the last of URL append some text like '&MC='. It may have Multiple 'Href'. Please help me on this.

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I've been using the command below which works well for finding the largest files in a certain folder.   find . -printf '%s %p\n'| sort -nr | head -10   However this provides output in KB only.   20160 /home/user/userfile   How can I change this command to show me results in MB, or GB? I can do this with du and get similar results but I am looking for a way to do this by tweaking the command above.

I am writing a simple helper function to show a specific folder in the format I want:  find . -maxdepth 1 -not -name "." -printf '[%TY-%Tm-%Td]\t%s\t%f\n' | sort -n   However I want to show the filesizes in a nicer format. I found  which I used to create a bash function called hr.  user@host:~$ hr 12345 12M   I tried using this in the find call as so:  find . -maxdepth 1 -not -name "." -printf '[%TY-%Tm-%Td]\t'$(hr %s)'\t%f\n' | sort -n   But it still continues to show the full filesize. How should I modify this so it works as expected?


Good programming habits questions.  Do additional using statements that the Class does not use affect the speed of the application?  Example I have a Class called StoreController -  using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc;   However, it only needs   using System.Web.Mvc; //Love some Resharerper   My question still, does it really affect the application to have the unused using statements?

For example, I rarely need:  using System.Text;   but it's always there by default. I assume the application will use more memory if your code contains unnecessary . But is there anything else I should be aware of?  Also, does it make any difference whatsoever if the same using directive is used in only one file vs. most/all files?    Edit: Note that this question is not about the unrelated concept called a , designed to help one manage resources by ensuring that when an object goes out of scope, its  method is called. See .


A powerful opponent made a long speech criticizing John. This speech was so powerful that it threatened John's political career. John decided to try to change his rival's opinion of him. To do this, he sent a letter to him asking for a favor.   Instead of using "try to change", can I use this expression "try changing"? Does it sound awkward? Grammatically wrong?

Is there any differences between      Try to do   And     Try doing   Thank you in advence.


Why do the following two lines return different results?  ("test" instanceof String) // returns false ("test".constructor == String) // returns true   Tested in the console of chrome version 28.0.1500.95 m  Does it work slightly differently for native types?

"foo" instanceof String //=> false "foo" instanceof Object //=> false  true instanceof Boolean //=> false true instanceof Object //=> false false instanceof Boolean //=> false false instanceof Object //=> false  12.21 instanceof Number //=> false /foo/ instanceof RegExp //=> true  // the tests against Object really don't make sense  Array literals and Object literals match... [0,1] instanceof Array //=> true {0:1} instanceof Object //=> true  Why don't all of them? Or, why don't they all not? And, what are they an instance of, then? It's the same in FF3, IE7, Opera, and Chrome. So, at least it's consistent.


The following question occurred to me while sketching out vector diagrams earlier today:  Do there exist positive integers $a, b, c, d$ such that $a^2 + b^2 = c^2$ and $a^2 - b^2 = d^2$?  In other words, do there exist any Pythagorean triples that share a "leg", and for which the "leg" of one is the "hypotenuse" of the other?  If not, can it be proven that such triples do not exist?  What I've tried: I've played around a bit with Euclid's formula, and it's easy enough to show that if such a pair of triples exists, it must be the case that there are integers $m$ and $n$ such that $$ d^2 = m^4 - 6 m^2 n^2 + n^4 $$ is a perfect square.  ($m$ and $n$ are the integers on which the triple $(a,b,c)$ is based.)  Similarly, if the triple $(a,d,b)$ is based on the integers $m'$ and $n'$, we end up with $$ c^2 = 2\left({m'}^4 + {n'}^4\right) $$ This latter equation looks a little more plausible as something that doesn't have integer solutions.  But I don't really know where to go from here, or even if this is the best way to think about it.

I have the following task:     Prove that the sum and the difference of two squares (not equal to zero) can't both be squares.   For the sum, I thought about Pythagorean triples: $x^2+y^2=z^2$ works for an infinite amount of numbers, but why can't it occur for the sum and the difference as well?  I tried to write down this:  Assume that $a^2>b^2$. Then $a^2+b^2=c^2$ and $a^2-b^2=d^2$. Summing the left and the right equation, we get $2a^2=c^2+d^2$. I am just stuck proving why this can't occur. Any ideas? Thanks for your help!


Stackoverflow has no "inbox" for users, yet in some circles (uncommon or new languages, specific topics) there are very few "experts" and some important questions get passed over as a result.  Is there any way to reach out to an "expert" (someone who has answered a question very well in a field related to the poster's question) without violating Stackoverflow rules like   1) Do not comment on one question asking a specific user to look at another question  2) Do not answer one question with a request for a specific user to look at another question?  Why has a messaging inbox not been implemented?

There has been quite a few times that I wished I could send a message to another user on SO - not ask a question for everyone to see, but just a short message informing them of something or requesting them to do something.  Are there any plans to allow this to happen in the future?  Related:


I had lost my iPhone, and I initiated the erase iPhone using iCloud. But, in the meanwhile, I found the iPhone. I am holding it in airplane mode, and it is still not wiped. I'm aware that if I turn on internet for it, it will probably start erasing all. I would love if I could cancel the erase command. Is this possible? Otherwise, I would just have to erase it, and back it up from iCloud backup. I would rather, not do any of that and just cancel the erase command. Is this possible?

I lost my phone on vacation and activated 'Lost Mode' for a couple of days. The night before heading home I decided to do the Remote Erase ´cause I thought there's no way I'd get it back, I also called my carrier and canceled the data service on my number. The phone has been offline ever since but the hotel just called to say they found my phone at the spa and they are mailing it back to me. So I want to cancel the 'Pending Erase', all I care about is recovering all the pictures from that trip that I hadn't backed up on iCloud yet... Will removing the device from my iCloud account work?  And if I don't have service on the phone, will the 'Erase iPhone' command still go through when I turn it on?  Please help! I have two days to figure this out


I've developed a solid understanding of principal component analysis to the point where I can actually write my own implementation of it in python. I fear this is the easy part where the hard part is rigorously developing an intuition for what the results will be for running PCA on a dataset and in determining whether PCA is the best method to use on my dataset.   Because the textbooks really dont go beyond defining what PCA is – they stop before telling me how to really use it, I'm looking for some advice into how I can play around with PCA to create a deeper appreciation for all its nuances.   I'm thinking I can test it on data with various covariance characteristics, i.e. random dataset, datasets with linear relationships among variables etc., but I'm not sure how to make these vague ideas concrete. Can you provide some examples of what kinds of datasets I can throw at PCA and how I can analyze the results to determine why they are what they are?

In today's pattern recognition class my professor talked about PCA, eigenvectors and eigenvalues.   I understood the mathematics of it. If I'm asked to find eigenvalues etc. I'll do it correctly like a machine. But I didn't understand it. I didn't get the purpose of it. I didn't get the feel of it.        I strongly believe in the following quote:     You do not really understand something unless you can explain it to your grandmother. -- Albert Einstein   Well, I can't explain these concepts to a layman or grandma.   Why PCA, eigenvectors & eigenvalues? What was the need for these concepts? How would you explain these to a layman?


What limits on the time-variance of the CMB do the COBE, WMAP, or Planck data put?  In other words, I am looking for a peer-reviewed paper that would answer this question: If I made maps of, say, WMAP Month 1, Month 2, Month 3, … data, would the timescale of the time-variance between the maps of the different months be much less than than cosmological timescales (say, the Hubble time)?  I do not want an answer that involves cosmology. I want a purely observational answer.

I know that the  is the leftover radiation from the "".   However, at every instant the surface is changing (at the rate of flow of time). So how constant is the CMBR?


Given a polynomial $p(x)$ that outputs an integer for every integer input $x$, is it necessary for $p(x)$ to have rational coefficients?

Let $f \in \mathbf R[x]$  and for every $k \in \mathbf Z$, $f(k)\in \mathbf Z$. Does this imply that $f \in \mathbf Z[x]$?   I tried to find a counter example, but my intuition tells me it's true and I don't know how to prove the statement either.


What is the difference between      "Listen my voice"   to     "Listen to my voice"?

Maximum time I face this problem by saying listening music. Is there any traditional cause behind this?  Can we use listen music or listening music?  Seems there is only a slight difference, but why is listen to music the right way to say it?


The product of manifolds without boundaries is always a manifold without boundary?  $\textbf{Example:}$ $S^2\times \mathbb R$ has a boundary?

Simple question but I am confused.  What is the boundary of $S^2\times\mathbb{R}$? Is it just $S^2$?  What would be the general way to evaluate the boundary of a product manifold?  Thanks for the replies!


The question here:  was asked a long time ago (2009) and earlier this year a solution was given by the user D.A. However, the user (now inactive) that posted the question has not selected it (or any other) as the answer.  After looking at "similar questions" while typing this out (e.g. ) , I see that this discussion has come up before. The counter argument is, "That's what voting is for." Back to the c++ question, the first answer, with 4 votes, is that c++ does not permit the desired behavior. Down below (at zero votes until I voted for it) is D.A.'s answer. Clearly, that counter argument only makes sense regarding answers that happened to be submitted at around the same time period, and have had an equal opportunity to receive votes. I would have completely missed the answer if I hadn't spent the extra time to look at the likely-wrong answers. If the site is to be helpful to users (and not just zombie accounts) then it makes sense for these kinds of answers to be marked as accepted so that they will be seen. Voting, in this scenario, is inadequate.

I have often come upon questions where the asker never bothered accepting what is obviously a correct answer. "Obviously" can mean (aside from my own judgment):   The answer is a clear leader in up-votes (again, combined with my judgment that it is a correct one) The answer is the only one (and again appears correct) The answer (or Q) is commented on by OP indicating it helped.   If the user is still active on SO, what helps sometimes is to post a comment on the question mentioning you can/should accept the answer. For my own answers, this technique worked ~30-50% of the time.  However, if the user is a zombie (showed up >1 month ago, asked one or few answers, and was not on the site for >1 month since), this would obviously not work.  To ameliorate this situation, I would propose allowing users whose rep > threshold to "accept" answers from other peoples questions. This would be limited to:   questions from zombie users as defined above (e.g. total active time on site <= 30% of time since last visit, or however you want to define). questions from non-zombie users with very low accept rates (this may require higher threshold).   In either case,   neither the OP nor "guest acceptor" gains 2 points for accepting. the OP should have the right to choose a different accepted answer at any time, and get 2 points rep when that happens. If you accept your own answer, you obviously don't get 15rep for acceptance.   I think if implemented to the above specs, it should provide enough of a barrier to misuse while serving the goal of the site (allow arriving at the best possible answer).  P.S. This was obviously triggered by some of my own answers but once I realized the situation I observed it numerously with questions I was merely browsing.


\begin{vmatrix}  a & b & b & \dots & b \\   b & a & b & \dots & b \\   b & b & a & \dots & b \\  \vdots & \vdots& \vdots & \ddots & \vdots\\  b & b & b &   & a\\  \end{vmatrix}  I still have no idea how to solve this determinant, please help me if you can:)

I have the following $n\times n$ matrix:  $$A=\begin{bmatrix} a & b & \ldots & b\\ b & a & \ldots & b\\ \vdots & \vdots & \ddots & \vdots\\ b & b & \ldots & a\end{bmatrix}$$  where $0 < b < a$.  I am interested in the expression for the determinant $\det[A]$ in terms of $a$, $b$ and $n$.  This seems like a trivial problem, as the matrix $A$ has such a nice structure, but my linear algebra skills are pretty rusty and I can't figure it out.  Any help would be appreciated.


If I have a table with the following information:    ParentID | ChildID ---------+--------      6   |      6       6   |      7       6   |      8       6   |      9       6   |     10    I need to display the distinct parent with all instances of child in the second column possibly concatonated with a comma e.g.    ParentID | ChildID ---------+--------    6     |     6, 7, 8, 9, 10   Thanks in advance!

Let's say I have a table of employees, like this:  Name     Sex     Role  Bob      M       Developer Joe      M       QA   Now, I have a problem with duplicated rows in this table. I will fix it sometime but it's not the issue. What I currently need is something that queries such a table:  Name     Sex     Role  Bob      M       Developer Bob      M       Janitor Joe      M       QA Joe      M       CEO   And will output the following rows:  Name     Role  Bob      Developer, Janitor Joe      QA, CEO   It doesn't matter to me if the "Role" will be split to separate columns or be a single column with multiple values.  Using SQL Server 2008 if it matters.


I need to use \right] in one of my lines, but if I don't write \left[ in the same formula I get an error (Using texmaker).  What I want to do is to type the range of a function, as in $F(x)]_{0}^{5}$. The problem is I can't use a regular bracket ] because of the line height (There are several fractions in there).   Is there any alternative to \right] that allows me to skip the left one?  I've seen several questions regarding curly braces (Problem being you need to write \left\{, but none that answers this particular question.

I have a very long equation that must be separated into two lines, and it has several pairs of nesting \left \right delimiters. Unfortunately, it seems that they need to be on the same line in order for them to work.  Also I'm using the align environment because I need the aligning functionality. Is there a way to have the size of delimiters automatically adjusted over multiple lines?


So basically as it stands I have a laptop which has no cd/dvd drive, and I don't have a usb drive.  The laptop has windows 7 installed with ubuntu 11.04 installed through wubi.  What I want to do is remove windows completely, and make ubuntu the only OS installed on the system.  Is there a way to do this without re-installing ubuntu? (i.e. can I take my wubi install away from windows?)  or is there a way to from inside ubuntu have it run the ubuntu iso somehow so I can just wipe the system and install it fresh? (even if it means I need to have an e.g. 2gb partition just for the image to reside in).

I want to install Ubuntu on my laptop that doesn't have a CD-ROM drive and I have no spare USB disk. I've tried Wubi, but that doesn't seem to work (since it prompts me to have the CD in the drive, which I don't have).  How can I install Ubuntu, easily and in a fast way?  P.s: I want to dual boot it with Windows 7 (which was preinstalled).  Edit:   When extracting the ISO to a folder and running Wubi it does install, but when I reboot the computer, it doesn't show GRUB, nor can I choose if I want to boot Ubuntu or Windows 7. After trying for the third time today, wubi gives me an error: Permission denied   I'm the administrator on the PC.


After having set innodb_file_per_table=1, dumping and dropping all db's, deleting ibdata1, and restarting mysql ... My ibdata1 file is small at last...  However, directly after reading in my dump, and seeing that all tables now all have their own big ibd files (approx 15GB), but still the ibdata1 is over 2.6 GB again...  The way I dump my data is with:  mysqldump --tab="D:\Mysql Databases\dumps\dump\%%a" --opt --single-transaction --no-autocommit -u root -p   This dumps to .sql (DDL / table structures) and .txt (actual data) files. These files I can use to recover with with:  create database myDb; use myDb; SET autocommit=0; SET unique_checks=0; SET foreign_key_checks=0; SOURCE *.sql; -- for each table COMMIT; SET autocommit=0; LOAD DATA INFILE '*.txt'; -- for each table COMMIT; SET autocommit=1; SET foreign_key_checks=1; SET unique_checks=1;   Why is the ibdata1 file growing again after enabling innodb_file_per_table and having succesfully shrunk ibdata1? And is there a way now to reclaim again this data, seen as all ibd data is already present per table?  Can I for example copy the small ibdata1 after recreating the database with the *.sql files, and placing back that ibdata1 file after reading in the data from the *.txt files?  Here are the non-default items in my.ini:  sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION" max_connections=151 tmp_table_size=256M thread_cache_size=20 myisam_max_sort_file_size=1G myisam_sort_buffer_size=32M key_buffer_size=64M innodb_log_buffer_size=8M innodb_buffer_pool_size=6G innodb_log_file_size=1G innodb_thread_concurrency=16 innodb_open_files=1000 join_buffer_size=2M max_allowed_packet=16M group_concat_max_len = 10M bulk_insert_buffer_size=512M collation-server = utf8_unicode_ci

I have innodb_file_per_table set and just today my ibdata1 file jumped from 59M to 323M after I made several changes to an 800M table to reduce it to about 600M. That particular table's .ibd file was reduced but the server's ibdata1 file went crazy. Any ideas?


Find the values of $R$ and $\alpha$ in the identities below, given that $R>0$ and $\alpha$ is an acute angle.  $$\sqrt{3}\cos{\theta}-\sin{\theta}=R\cos(\theta+\alpha)$$  I'm a bit confused by this task.  How should I start? I have $$ \cos(a+b) = \cos(a)\cos(b)-\sin(a)\sin(b). $$       If I square anything, I can use the trig identity  $$ \sin^2(x) + \cos^2(x) =1. $$

Express $\sqrt{3}\sin\theta - \cos\theta$ as: $a\cos (\theta + \alpha) $  Can someone please explain to me how to go about doing this?


My colleagues and I are attempting to run some updates on a computer with Ubuntu 12.10, which has been unused for some time. However, when we try running sudo apt-get update the terminal returns several error messages, of which here is a sample:  W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-backports/main/binary-i386/Packages  404  Not Found [IP: 91.189.91.13 80]  W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-backports/restricted/binary-i386/Packages  404  Not Found [IP: 91.189.91.13 80]  W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-backports/universe/binary-i386/Packages  404  Not Found [IP: 91.189.91.13 80]  W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-backports/multiverse/binary-i386/Packages  404  Not Found [IP: 91.189.91.13 80]   The full log is here:   I've heard some have had the same problem, apparently Ubuntu cannot handle large amounts of updates? At the moment, we have about 500 to install :(  How would we go about fixing this problem? Thanks for the assistance.

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


So I was given a question that begins like this.     Let $P_{\text{fin}}(\mathbb{N})$ be the following set (called the finite power set of $\mathbb{N}$):    $$ P_{\text{fin}}(\mathbb{N}) = \{X \subseteq N \,\mid\, X \text{ is finite}\} $$      Prove that this set is countably infinite.   From my understanding of Cantor's theorem, I assumed that the Power set of natural numbers has the same cardinality with the real numbers. So, it is uncountable. Apparently in this question it is true that it is countable infinite, but i do not understand how to prove this.

Show that the set of all finite subsets of $\mathbb{N}$ is countable.   I'm not sure how to do this problem. I keep trying to think of an explicit formula for 1-1 correspondence like adding all the elements in each subset and sending that sum to itself in the natural numbers, but that wouldn't be 1-1 because, for example, the set {1,2,3} would send to 6 and so would the set {2,4}.  Multiplying all the elements in each subset and sending that product to itself in the natural numbers wouldn't work either since, for example, {2,3} would send to 5 and so would the set {1,5}. Any ideas?


I want to upgrade from Android 4.1 to 4.3 on my Sony Xperia SP smartphone.  Please, how do I go about it to have a successful outcome without losing what I have already on the phone?

This Community Wiki question is designed to be the "canonical question" for questions asking how to upgrade one's device to a new Android version.   I want to get a newer version of the OS for my Android device. How can I do that?  See also:


Why will this code not print out a string?  String s = "My name is Jack";     String[] arr = s.split("");     char[] a = Arrays.toString(arr).toCharArray(); System.out.println(a); System.out.println(new String(a));

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the  of the array, as defined by Object.toString():  int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray);     // prints something like '[I@3343c8b3'   But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs:  // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5]  // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob]


It is one of the things, which make me crazy in salesforce. You create a custom button, which opens a page. It works fine in your org, but it fails in managed package org, in addition it should be adjusted for lightning environment...  And you cant test it until deploy it to managed package org and there you cant fix the issue >:-]  Any way, could you please provide a simple solution to create button, which will be on standard lightning layout and which opens a visualforce page in managed package org. I thought to do something like this:  window.open('{!URLFOR($Page.SomePage,'',[id=someValue])}   But it won't work, as $Page is not work in custom buttons\links or i dont know how to use it.  Then i thought to get somehow namespace with using soap call from javascript:  {!REQUIRESCRIPT("/soap/ajax/36.0/connection.js")} {!REQUIRESCRIPT("/soap/ajax/36.0/apex.js")}  var nameSpace = sforce.apex.execute("orgNamespace.Util", "getNamespace", {});   but again, we have to know namespace in order to reach the class...[facepalm]  Will be grateful for any solutions!

When you have a dedicated Visualforce Page and can use modern JavaScript Remoting techniques, this is seldom an issue. But I'm looking at some historical code in a managed package like this:  {!REQUIRESCRIPT("/soap/ajax/29.0/apex.js")}  var result = sforce.apex.execute(     "ns.WebServiceClass",     "someWebServiceMethod",     {"arg1": "foo", "arg2": "bar"} );  alert(result);   The ns is baked in. While this JavaScript can be deployed to another development org, the web service invocation will not execute as the class doesn't have a namespace prefix in this environment.  Same problem applies to Custom Button or Link URLs. Surely URLFOR('/apex/PageName') would resolve the namespace prefix; after all the button is a managed component with the namespace on it. But it doesn't work the same magic that new PageReference('/apex/PageName') does in Apex.  I've seen a few approaches including (but not limited to):   maintaining a list of manual deployment steps, using some precompile task (eg Ant) to tokenize the namespace prefix,   Can you gurus share any other techniques?


My project is not very advanced cause I've just started programming in Java/JavaFX.  Users select country from combobox, then below in text field write a city. After pressing OK button user should receive a weather forecast for one day for the city entered. Actually names are getting correctly from inputs and sets as private fields in Weather class. I'm using weather OWM JAPIs from: . All needed libraries are added to project. (I've read that better way is to use Maven/Gradle frameworks but i'm totally green in using them).  Problem appears when method showCurrentWeather from Weather class is launched. New created object owm in line 19 causes lot of errors f.e:  Caused by: java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics at net.aksingh.owmjapis.core.OWM.<init>(OWM.kt) at sample.Weather.showCurrentWeather(Weather.java:19) at sample.Controller.searchWeather(Controller.java:30)   Weather class:  public void showCurrentWeather() throws APIException {      OWM owm = new OWM(MyConstants.OWM_API_KEY);     CurrentWeather cwd = owm.currentWeatherByCityName(city);     System.out.println("City: " + cwd.getCityName());     System.out.println("Temperature: " + cwd.getMainData().getTempMax()             + "/" + cwd.getMainData().getTempMin() + "\'K"); }   Controller class  public void searchWeather() throws APIException {      String selectedCountry = comboBox1.getSelectionModel().getSelectedItem().toString();     String selectedCity = textField1.getText();     Weather weather = new Weather(selectedCity,selectedCountry);     weather.showCurrentWeather(); }   Any answer/advice is really appreciated.

I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this?


I have US L1 visa on passport that expires in Jan2014. I am planning to visit India in Jan2014-Feb2014. I have my US H1 visa for which I will go to stamping in India. Now, can I travel through London? The visa I have on passport is for L1 that expires in Jan2014, but my return date is in Feb2014 and I will be coming back on H1. I will be transiting through London between 6th Jan 2014 to 12th Jan 2014.   I read few other similar questions but unable to judge whether to have valid US visa for return date or while passing through london.

I am travelling to Budapest and therefore have a Schengen Visa. I hold an Indian passport and a valid US visa. I'm travelling from Chicago-Heathrow-Budapest and returning by Budapest-Dublin-Chicago.  Would I need a transit visa for UK/Ireland?  UPDATE  Hoping this will help someone someday.   I was not allowed to board my return flight (BUD-DUB-ORD) because I do not hold an overnight Irish Transit Visa. They said I could have transited happily if the connecting flight was in the same day, but because I would have to originally land at 10 PM and catch the connecting flight next morning at 10 AM, I needed a transit visa. Well, I thought it was BS, but couldn't help comply with the rules. I booked another last minute ticket and flew via Warsaw via LOT.


I want to delete all .ppm and .png files under current directory. So after checking some web pages about the usage of "find" command on the Internet, I typed the command below:  find . -type f \( -iname ".png" -o -iname ".ppm \) -exec rm {} \;   but the Terminal just showed a  >   and did not do anything. What was wrong with it?

When I enter single quote ' in terminal it goes to some other mode, and commands don't execute. What is this mode and when do we use it?  root@sai:~# ' > ls > ' ls : command not found root@sai:~#


Each time I put a bootable drive in the usb slot, it asks me if I want to install it. Can I use it to reinstall my OS without formatting my harddrive?

Recently I installed Ubuntu 12.10 x64 Server Edition on my PC. Unfortunately, I attempted to install a lightweight desktop but due to the fact that I have an old graphics card, the PC does not perform so well. I am thinking of re-installing an Ubuntu version but I do not want to lose the contents in my home folder. Is there any way to do that with a Live CD?


I'm looking for modern textbooks on quantum mechanics that treat topics such as quantum entanglement , bell's theorem , quantum teleportation , quantum information theory , The Many-world interpretation , decoherence etc . All the textbooks that I can find cover the usual topics only (scattering theory , perturbation , the hydrogen atom etc ) But I can't find a book that mainly address these topics . Are there textbooks that specialize in the aforementioned topics ? If not , What are some pedagogical papers that are useful ?  I don't care if the resources are mathematically rigorous or not . I would actually prefer books /papers that use more advanced math than usual.

I have a good undergrad knowledge of quantum mechanics, and I'm interesting in reading up more about interpretation and in particular things related to how QM emerges algebraically from some reasonable real world assumptions. However I want to avoid the meticulous maths style and rather read something more meant for physicists (where rigorous proofs aren't needed and things are well-behaved ;) ) I.e. I'd prefer more intuitive resources as opposed to the rigorous texts.       Can you recommend some reading to get started?