I am creating a site that I expect to receive DDoS attacks on occasion.  I have created two EBS AMIs on Amazon EC2. One AMI for a MySQL Database and one for the web host.  I have added an elastic IP to the web host server and have attached an A DNS record to it via Route 53 so I can access my domain.  If I were to create a load balancer, would I have to change the DNS record for the website to the load balancer's ip address? And then simply start as many instances of the web hosting ami under the load balancer as the DDoS calls for?  Is this thinking even somewhat correct?

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


In Windows you can visualize the desktop with the combination Windows-key + d.  Is there something like this in Ubuntu (16.04)? Can I implement it in some way?

I just upgraded to 11.10 from 11.04. Previously the shortcut to show the desktop was Super +D (same as in Windows), But now it is not working. What is the new shortcut?


I am an Indian passport holder. I am travelling to Greece via Istanbul (Turkish Airline) from 10th to 25th June. My return flight to New Delhi from Athens has an 8 hour layover and I am considering applying for a transit Visa to take a look around Istanbul for a couple of hours. However, my Schengen Visa application is already under process and I haven't declared on the Schengen Visa application form that I intend to apply for a Turkey transit Visa. Will it pose a problem? If not, can I apply for an e-Visa and get a transit Visa for Turkey online? What do I need to keep in mind? This is my first international travel and any advice is appreciated. Thanks! Sruti

Do I need a transit visa at Istanbul Airport to enter Istanbul for city sightseeing or hotel accommodation?. All services provided free by the Turkish Airline. I am Nigerian citizen and booked Turkish Airline flight to Nigeria with 12hours layover at Istanbul Airport.


I am running OSX Yosemite. I had free space on my partition, (see picture below) but now it wont delete. I change the format to Mac OS Extended (Journaled), and then when I hit the " + " button it loads for about 1/100 of a second, and then shows on the screen that it partitioned it. When I click away from the partition tab onto the first aid tab, it goes away and becomes free space again. (NOTE: I am trying to MERGE the free space with my first partition, not make a new partition, but i have to make a new one to merge it with my first partition.)

I bought a new SSD with 750 GB and made two partitions: 600 GB and 150 GB. The smaller one was thought to be a Bootcamp partition one day, but to date it was just another unused partition. When I needed more space, I decided to merge these two partitions. The partition was created with Mavericks, the merge was done with Yosemite.  I opened Disk Utility and the "minus" button. Disk Utility told me both partitions would be merged then. However it miserably failed. My main hard disc suddenly had errors which couldn't be repaired and even two of my other external hard discs could not be mounted any longer.  I eventually restored the hard disc from Time Machine, which worked well.  My second partition is now listed as free:    Unfortunately I can't resize the 600 GB partition nor can I create a new partition using the free space.  Diskutil reveils the following:  ~  diskutil list /dev/disk0    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      GUID_partition_scheme                        *750.2 GB   disk0    1:                        EFI EFI                     209.7 MB   disk0s1    2:          Apple_CoreStorage                         599.6 GB   disk0s2    3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3 /dev/disk1    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:                  Apple_HFS Macintosh HD           *599.3 GB   disk1                                  Logical Volume on disk0s2                                  XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX                                  Unencrypted   Also diskutil brought up this:  ~  diskutil cs list CoreStorage logical volume groups (1 found) | +-- Logical Volume Group 9D2BA4BA-xxxx-xxxx-xxxx-xxxxxxxxxxxx     =========================================================     Name:         Macintosh HD     Status:       Online     Size:         599640592384 B (599.6 GB)     Free Space:   6111232 B (6.1 MB)     |     +-< Physical Volume 29A9A02B-xxxx-xxxx-xxxx-xxxxxxxxxxxx     |   ----------------------------------------------------     |   Index:    0     |   Disk:     disk0s2     |   Status:   Online     |   Size:     599640592384 B (599.6 GB)     |     +-> Logical Volume Family 2FA7892F-xxxx-xxxx-xxxx-xxxxxxxxxxxx         ----------------------------------------------------------         Encryption Status:       Unlocked         Encryption Type:         None         Conversion Status:       NoConversion         Conversion Direction:    -none-         Has Encrypted Extents:   No         Fully Secure:            No         Passphrase Required:     No         |         +-> Logical Volume 7BF42B7B-xxxx-xxxx-xxxx-xxxxxxxxxxxx             ---------------------------------------------------             Disk:                  disk1             Status:                Online             Size (Total):          599282155520 B (599.3 GB)             Conversion Progress:   -none-             Revertible:            No             LV Name:               Macintosh HD             Volume Name:           Macintosh HD             Content Hint:          Apple_HFS   I have tried this:    fsck -fy (The volume Macintosh HD appears to be OK.)   but it wouldn't help. It said I couldn't recover because it wasn't created in a way it would support (sorry for missing the exact message).  I then have learned that Apple_CoreStorage might indicate my disk is encrypted, which might explain why I can't resize it. It doesn't explain why I can't create a new partition to me.  What are my options to make my hard disk available in a single partition with size 750 GB?


I've read in some Skyrim related sites that many players have had problems with: 1) Items in their inventory that are related to quests but don't work as expected. (Plantea's flute, amulet of Talos, the 4 little things used in The Lost Ages quest, etc.) 2) Related issues to quest that requires an event to trigger it. (The Lost Ages won't become active even when you read the book The Aetherium Wars. Another example is when you kill the Boethia's priest, if you read the book while it's on his body will make the Ebony Mail inaccessible at the end of the Boethia's Calling quest) 3) Visiting places that store special items related to a quest or not talking to people that gives you quests before you enter and "clean" those places. Probably there are more common issues, but now I just remember those. I've already asked: . The comments left by Batophobia were useful and I hope I can explain myself better this time. According to my own experience, those problems could've been avoided if I'd have known the right order. (Instead of killing everyone in a cave, first I should talk to X or read Y, for instance) So, what I'd like to know is the right order of missions. What I've tried is to finish a quest as soon as I get it, but not always work: when I'm in the middle of a quest and I get another, and if I start the second when I finish the first, sometimes is too late. I'm not asking about a specific quest, I know. And I know this is not allowed in this forum. If you find this question too broad, please let me know how I should ask, because I haven't been able to play Skyrim without these issues and I'm getting tired of them. In  question I got this comment: In that case I suggest saving and trying it. Worrying about every single potential bug in a Bethesda game will drive you crazy. –  kotekzot. Call me crazy then, but I want a bug- or glitch-free Skyrim play. I'm playing on Xbox. Feel free to edit and/or to penalize this question; English is not my native language.

What's amazing about these open world games is the freedom I have as a player. If I don't want to follow the main story line for a while, and just explore, I can do that, and the game won't break.  On the other hand I don't particularly like the feeling of having made a significant, bad choice in the game, among the lines of Yeah, that dialog option you selected hours ago? This amazing quest line is now off limits.  If I recall correctly, in Morrowind, I had to progress through a few different guilds' quests in the right order, otherwise it'd have stopped my progress in a few guilds.  As a Skyrim example, it doesn't appear that the very first choice made in Helgen at the very beginning has much significance. If someone told me It's not that significant, you still get to choose sides (or, rather not told me "This is important"), that'd help.  Another example: Based on a question I read here, I should probably make sure that I don't throw away any of the dragon priest masks and need to make sure to collect one during a specific quest. This would be relevant for this topic if I could easily miss it otherwise while doing that question.  This includes accidental problems possibly caused by bugs: It appears .  It doesn't matter too much which of the love triangle guys in Riverwood I support: That's not nearly significant enough.    Are there non-obvious, hidden decision points in the quests and story lines? When playing in a certain area, doing a certain quest, what do I need to make sure to do or not do, to not accidentally prevent me from getting or achieving something significant?  I still want to explore on my own, but want to be aware of which choices are important.  This is somewhat related to .


I ran a regression in which I have an interaction term of two factor variables.  The one of the variables has 2 levels: Condition_A & Condition_B (therefore the first one is the reference category) but the other one is called Group.Membership has 3 levels: Group_1, Group_2 & Group_3 (therefore the first one is the reference category).  What I am not sure about is how to interpret the output. What I get as part of the lm() ouput is :       ConditionB:Group.Membership.L         (Beta and p-value)     ConditionB:Group.Membership.Q         (Beta and p-value)   Should I interpret the .L as the coefficient for Group_2 compared to the reference category (Group_1), and the same goes for .Q? Or there is another interpretation of this type of output?  Thank you for your help!  EDIT ----------------  I have another question. I have tested the interaction term of the Condition variable with many other factor variables. Why sometimes I get in the ouput the .L and .Q in the end, whereas in other occasions I get the levels of the second variable of the interaction term without the .L and Q.? Am I doing something wrong in my lm() ?

I have asked a similar question here:  I am puzzled by the interpretation for an interaction term. In my data my Y is an interval variable with the health outcome of an experiment. I have used an interaction term in which I have interacted the condition with the predisposition of the subject considering health status at base level. They are both categorical variables (factor variables in R).  Now it gets complicated because the Condition was two treatments: in treatment A subjects got the placebo first and then the real medicine whereas in treatment B they go the real medicine first and the placebo second. All it changes is the order.   Health outcome = a + Condition * Health.Base   I have the worst state of health at the base level as my reference category I find that interaction with the Condition is statistically significant but I am not sure how to interpret this.  I use the lm() function of R (although my design looks more like an ANOVA) and in the output I get the b coefficient in an output that looks like this:  ConditionB:Health.Base.So.and.So         (Beta and p-value) ConditionB:Health.Base.Excellent         (Beta and p-value)   A statistically significant interaction term for those in Excellent health at baseline would mean that they are affected by the Condition B more than Condition A compared to the reference category people (Poor health at baseline). Is this right? What does the beta-coefficient represent?   If I would like to examine for each Health category at the base line separately without comparing to a reference category I would have to code each category as a dummy variable. However, in this case I would compare whether membership to a specific health status at the base line significantly changes between conditions compared to those who belong to the other health statuses at the base line. Is this right? Again, what does the beta-coefficient represent?  Would it be right to assume that the choice of the interaction between the Condition and the dummy variables is easier to interpret?  --- EDIT --- R output:  Call: lm(formula = HealthOutcome ~ Condition * HealthStatus,      data = datA)  Residuals:     Min      1Q  Median      3Q     Max  -1.5957 -0.5942 -0.2640  0.4423  2.4423   Coefficients:                                        Estimate Std. Error t value     Pr(>|t|)     (Intercept)                            2.595652   0.053044  48.934  < 2e-16 *** ConditionCondB                        -0.001449   0.077071  -0.019    0.985     HealthStatusSo.and.So                 -0.331693   0.078094  -4.247  2.35e-05 *** HealthStatusExcellent                 -0.836724   0.092692  -9.027  < 2e-16 *** ConditionCondB:HealthStatusSo.and.So   0.137490   0.110612   1.243    0.214     ConditionCondB:HealthStatusExcellent  -0.199787   0.133943  -1.492    0.136     --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  Residual standard error: 0.8045 on 1059 degrees of freedom   (68 observations deleted due to missingness) Multiple R-squared:   0.16, Adjusted R-squared:  0.156  F-statistic: 40.33 on 5 and 1059 DF,  p-value: < 2.2e-16


I liked having my name in the top bar. It was a nice visual indication that I was logged into the site.  I also liked having a ♦ as a visual indication that I was a moderator on a site.  Now my name is gone, there is only my avatar, which at this size is just some random unrecognizable picture. (Ok, more recognizable than the .)  Please bring back the user name.  To make room, you can take out the list of badges. I never saw the point of these. Reputation, yes, I guess many people like to see it, and for people like me who participate on multiple sites it indirectly tells me which privileges I have on the site. But the badges? They don't change often, they have zero impact, they can stay in the profile page.

A minor suggestion, but I actually loved having my username there. This would make icon size issues I've seen others complain about simply... go away.  I stole this idea from .


1 Month Old Sandisk Cruzer Blade 16 GB. Became write protect while trying to copy 13 GB data from a friend's computer using Windows 7. Suddenly transfer stopped because of write protect. Did scan for malicious viruses in my computer running on Windows 10. Windows Defender finds worms and Trojan win32 and destroys it. But its back. Not able to format the usb because of write protect. Did  1. Quick format 2. in regedit added value of WriteProtect in StorageDevicePolicies to 0 3. There is no way for gpedit.msc since my system is running on Windows 10 Home edition 3. In disk part, able to make attributes as readonly but not able to clean because of write protect 4. in Disk management no option to format at all  5. Tried using third party softwares like usbfixer, HDD low level format tool and HD Tune Nothing worked because of write protect.  How to remove write protect?

When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


In light clock thought experiment,if the observer is moving with velocity v relative to the light source&mirror frame ,then why path of light bends? According to einstein's postulate speed of light is independent of source motion??

If I am standing on a platform moving along the X-axis and I throw a basketball vertically upward along the z-axis, the ball also travels along the x-axis. Does the same apply to a photon? According to a special relativity postulate  speed of light is not affected by the velocity of the inertial frame or the velocity of the emitter. If this postulate is true, shouldn't a photon fired vertically as above should travel only along the z-axis but not along the x-axis?


I want to get the truncation error of    $$ u'(x) \approx -\frac{1}{h} \left(\frac{3}{2}u(x) - 2u(x+h) + \frac{1}{2} u(x+2h)\right) $$   The idea is to show that the expression of the right is equal to $u'(x) + O(h^3)$. I have been stuck for two days. If anyone at least knows the name of the approximation I would really appreciate it.    Here's what I have so far:  If we drop the $h$ that is dividing, we have that  $$ - \left(\frac{3}{2}u(x) - 2u(x+h) + \frac{1}{2} u(x+2h)\right)  = \frac{3}{2} (u(x+h) - u(x)) + \frac{1}{2}(u(x+h)-u(x+2h)) $$  and we must prove that this equals $u'(x)h + O(h^4)$ so that when we divide by $h$ we get what we wanted.  I can apply the Taylor expansion centered in $x$ to the first term, for example, and centered in $x+2h$, to the second term.  I get $$\frac{3}{2} [u'(x)h+u''(x)\frac{h^2}{2} + u'''(x) \frac{h^3}{6} + O(h^4)] + \frac{1}{2} [-h u'(x+2h) + u''(x+2h) \frac{h^2}{2} - u'''(x+2h) \frac{h^3}{6} + O(h^4)]$$  Separating a $u'(x)h$, so I can continue working with a term I want to show is $O(h^4)$ (remember that I will need to divide by $h$ after), and rearranging terms a little bit I get:  $$u'(x) h + \frac{1}{2}h [u'(x) - u'(x+2h)] + \frac{3}{4}u''(x)h^2 + \frac{1}{4} u'''(x)h^3 + \frac{1}{4} u''(x+2h)h^2 - \frac{1}{12} u'''(x+2h)h^3 + O(h^4)$$  Doing the Taylor expansion to $u'(x) - u'(x+2h)$, centered in $x$ (an observation is that I could have chosen to center in $x+2h$), we get:  $$u'(x)h + \frac{1}{2}h[-u''(x)2h - u'''(x)2h^2 + O(h^3)] + \frac{3}{4}u''(x)h^2 + \frac{1}{4} u'''(x)h^3 + \frac{1}{4} u''(x+2h)h^2 - \frac{1}{12} u'''(x+2h)h^3 = u'(x)h + \frac{1}{4}h^2 [u''(x+2h)-u''(x)] - \frac{3}{4}u'''(x)h^3 - \frac{1}{12}u'''(x+2h) h^3 + O(h^4)$$  Again, I have a decision to make, and I choose to change the expression in brackets to $u'''(x) 2h$ (with the Taylor expansion centered in $x$).  But then I get $$u'(x)h - \frac{1}{4}u'''(x)h^3 - \frac{1}{12} u'''(x+2h)h^3 + O(h^4),$$ and I can't...finish it.  This is only one of many attempts. I checked my calculations, but it might be a calculation error on my part. Maybe at signs or coefficients at the Taylor expansion I just can't find it.  Thank you, Billy.

I'm not really sure how to go about this.. any help is appreciated.


I have such a string :  CN=whatevername,OU=whatever1,OU=whatever2,DC=domain,DC=com   And I'm trying to get which is following "OU" until next comma. So in my example, I would like to receive "whatever1" and "whatever2".  I have tried this but it returns me the rest of the string until last comma.  (?<=OU=).*(?=,)   Thank you.

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


When beginning my education, I regarded nearly everything as continuous and analog in nature:    Physical objects could have any mass on a continuous scale Light sources could emit any intensity of light on a continuous scale   The more I learn, the more I find what I regarded as continuous is actually discrete:   Physical objects are composed of discrete numbers of atomic and subatomic particles Light sources emit a discrete number of photons   This trend of finding that things are actually discrete seems to be part of unraveling the properties of nature. The further you dig into something, the more you find the basic elements that comprise it.   It seems strange to me that anything could be truly continuous in nature since such a thing could potentially store infinite information. Is there anything in the universe that we know with relative certainty is not discrete?   Edit: This isn't really a duplicate of the question that is linked. That question is essentially asking, "does the Planck scale imply that space is discrete?" This is not the same as "is everything in the universe discrete?" I did not find the answer to my question there as the answers are addressing a different question.

On a quantum scale the smallest unit is the , which is a discrete measure.  There several question that come to mind:   Does that mean that particles can only live in a discrete grid-like structure,  i.e. have to "magically" jump from one pocket to the next? But where are they in between? Does that even give rise to the old paradox that movement as such is impossible (e.g. )? Does the same hold true  for time (i.e. that it is discrete) - with all the ensuing paradoxes? Mathematically does it mean that you have to use difference equations instead of differential equations? (And sums instead of integrals?) From the point of view of the space metric do you have to use a discrete metric (e.g. the ) instead of good old Pythagoras?   Thank you for giving me some answers and/or references where I can turn to.  Update: I just saw this call for papers - it seems to be quite a topic after all: Is Reality Digital or Analog? FQXi Essay Contest, 2011. , , . One can find some pretty amazing papers over there.


Assuming $f:[a,b]\to\mathbb{R}$ is continuous, how do you prove that the following function is continuous?  $$h(x)=\sup\{f(t): t\leq x\}$$

Exercise:   Suppose that $f$ is continuous on $[a,b]$ and that $F(x) = \sup f([a,x])$. Prove that $F$ is continuous on $[a,b]$ .  Attempt of proof: Suppose that $f$ is continuous on $[a,b]$ and that $F(x) = \sup f([a,x])$. Then since $f$ is continuous on [a,b]. Then by definition  $f$ is continuous at a point $c$ in $(a,b)$ iff for every $ε > 0$ there is a $δ > 0$ such that $|c-x| < δ$  $→$ $|f(c) - f(x)| < ε$.  Then we need to show $F$ is continuous.   Then let $ε > 0$, then there is a $δ>0$ such that $|c-x| < δ$.   Then, $|F(c) - F(x)| = |\sup f([a,c)] - \sup f([a,x)]|$.  Can someone please help me? I am stuck and don't know how to continue. Thank you in advance.


When I tried to run this program  couple of times the final value of i is 11407, 11417, 11400 etc. before displaying stack overflow error. Why is the final value of i not same every time this program is executed?  public class MainRecursive {     static int i=0;      public static void main (String arg[])     {         i++;         System.out.println(i);          main(arg);     } }

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


Determine all the matrix A 3x3 in R such as AB=BA for all B 3x3 in R (without determinants)

The question is from Axler's "Linear Algebra Done Right", which I'm using for self-study.  We are given a linear operator $T$ over a finite dimensional vector space $V$. We have to show that $T$ is a scalar multiple of the identity iff $\forall S \in {\cal L}(V), TS = ST$. Here, ${\cal L}(V)$ denotes the set of all linear operators over $V$.  One direction is easy to prove. If $T$ is a scalar multiple of the identity, then there exists a scalar $a$ such that $Tv = av$, $\forall v \in V$. Hence, given an arbitrary vector $w$, $$TS(w) = T(Sw) = a(Sw) = S(aw) = S(Tw) = ST(w)$$ where the third equality is possible because $S$ is a linear operator. Then, it follows that $TS = ST$, as required.  I am, however, at a loss as to how to tackle the other direction. I thought that a proof by contradiction,  ultimately constructing a linear operator $S$ for which $TS \neq ST$, might be the way to go, but haven't made much progress.   Thanks in advance!


In ZF with GCH, can we prove that the power set of every well ordered set can be well ordered?

Without appealing to the axiom of choice, it can be shown that (Proposition:) if $X$ is well-orderable, then $2^X$ is totally-orderable.  Question: can we show the stronger result that if $X$ is well-orderable, then so too is $2^X$?  Proof of Proposition. Pick any well-ordering of $X$. Then the lexicographic order totally orders $2^X$.  More explicitly: for any two $f,g \in 2^X$, define $f < g$ iff   there exists $x \in X$ such that $f(x) \neq g(x)$, and if $x \in X$ is minimal such that $f(x) \neq g(x)$, then $f(x)=0$ and $g(x)=1$.   It can be shown that $<$ totally-orders $2^X$.


My ArcGIS 10.5 performance is very slow just in opening some thinks like: Options, tables, labels, arctoolbox, draw menu ect. It open the mentioned things in about 3 minutes.  I have tried different solutions like: l deleted Normal.mxt, remove and reinstalled the ArcGIS, restore my PC and tried more solutions that I found in Internet but no one was useful to solve the problem. My Computer  is Dell 5559 cori7 2.5GHz 4cpus, 8GB ram and 4GB Graphic dedicated memory This is bothering me. What is the problem?

I have a recent installation or ArcGIS Desktop on a 64 bit Windows 7 Machine, with 8GB ram, intel core i7 processor, and a solid state drive.  It takes ~2 min to open either ArcMap or ArcCatalog from the start menu (e.g. without loading any data).  As a new installation, I have only the default folder connections.  Is this normal, or is it possible that there is something wrong with my installation?


I have a class with methods which I want to use as callbacks. How to pass them as arguments?  Class MyClass {      public function myMethod() {         $this->processSomething(this->myCallback); // How it must be called ?         $this->processSomething(self::myStaticCallback); // How it must be called ?     }      private function processSomething(callable $callback) {         // process something...         $callback();     }      private function myCallback() {         // do something...     }      private static function myStaticCallback() {         // do something...     }     }   UPD: How to do the same but from static method (when $this is not available)

How can I dynamically invoke a class method in PHP? The class method is not static. It appears that   call_user_func(...)   only works with static functions?  Thanks.


How do you change the icon for a Windows Application on the Start Menu? My specific target is Skype.

I'd like to change the icon of a app downloaded from the store. I googled it but just found out how to change basic icons like the desktop, bin, ...  Is it even possible to change windows-foreign icons?  At the image you can see which app I mean (ColorNote)


I am trying to determine if the selected element is a input type element.  var element = this.getElement(); console(element) => <input type='text' name='input' value ='test'> or something else   How do I check if selected element is input element.  I searched google and someone said it can be  element.is('input') but it gave me error saying is undefined.   Can anyone help me here? Thanks a lot!

I need a way to determine the type of an HTML element in JavaScript. It has the ID, but the element itself could be a <div>, a <form> field, a <fieldset>, etc. How can I achieve this?


Let $K $ be a subfield of $\mathbb C$ not contained in $\mathbb R$. Is $K$ dense in $\mathbb C$?   My problem is I have never used the concept of dense set in algebra and neither have any idea about using sequences here. Please give some hints

Let $K$ be a subfield of $\mathbb{C}$ not contained in $\mathbb{R}$. Show that $K$ is dense in $\mathbb{C}$.     completely stuck on it. can I get some help please.


I have a cube, and I would like it to have a text inscribed in it, so the text would be in the cube but we could see it. Is it possible to do this?

Coming from SketchUp one of the tools I miss most is the circle draw tool which lets you draw a circle on any face and then you could extrude it in/out. The only tool that I know of that comes close to this is the knife tool but this would be very impractical to cut out with the knife  Example:    Is there any tool in blender that can match this function? also how could you do this with squares?


I'd like to use advance mode and programming mode in calculator. but it is not showing mode option button in 16.04 ubuntu. How to enable the calculator mode button.

I am trying configure the Calculator to do some binary to hexadecimal conversions but I can't seem to get to scientific mode. Please can someone tell me how I configure?


I know I have spatial analyst licensed and the tool works fine within ArcMap but when I try to run this code snippet:  import arcpy  arcpy.CheckExtension('Spatial')  # which returns 'Available'  arcpy.gp.ExtractByMask_sa("D:/Sheyenne/Atmospherically Corrected Landsat/Just_bands/LT50300281984137PAC00_sr_band3.tif", "D:/Sheyenne/sheyenne_area_poly.shp", "D:/Sheyenne/Atmospherically Corrected Landsat/Practice_band_clipLT50300281984137PAC00_sr_band3.tif")   the error returned is:  ExecuteError: Failed to execute. Parameters are not valid. ERROR 000824: The tool is not licensed. Failed to execute (ExtractByMask)   Has anyone encountered this before?

If I run this script:  import arcpy arcpy.AddMessage(arcpy.CheckExtension("Spatial")) from arcpy.sa import Con from arcpy import env fDir=r'd:\scratch\fdir' outFolder=r'd:\aerials\images' env.workspace = outFolder fDir=arcpy.Raster(fDir) Gter=Con(fDir> 1,2) Gter.save("TEST")   from ArcGIS, the output is:    When I run it as stand-alone script, it is very different story:    How do I access Spatial Analyst extension from a stand alone script?


I want to create a ZIP archive of a directory without going into the directory itself, and not include that directory    - This post guides to changed the current directory and then create the archive. But, as stated earlier, i do not want to change the current directory.  This is the structure of the directory that I want to archive  parentdir/ parentdir/dir1/ parentdir/dir1/file1.txt parentdir/dir1/file2.txt parentdir/dir2/ parentdir/dir2/file1.txt parentdir/dir2/file2.txt   And the desired archive would contain  dir1/ dir1/file1.txt dir1/file2.txt dir2/ dir2/file1.txt dir2/file2.txt   If I use the command  zip -r output.zip parentdir/   this includes the parentdir as well in the archive.  Is there any flag that allows us to create an archive without the parentdir ? I do not want to change the current directory to the parentdir. I cannot also use the -j flag,since I do not want to junk the rest of the paths. Can i accomplish this from any directory?

I have a directory called folder that looks like this:  folder       -> root_folder                     -> some files   I want to zip this directory into zipped_dir, I tried:  zip -r zipped_dir.zip folder/*   But this generates a ZIP that looks like this:  zipped_dir           -> folder                    -> root_folder                                  -> some files   in other words, it's including the directory whose contents I want to zip. How can I exclude this parent directory from the ZIP, without moving anything?  IE I would like this end result:  zipped_dir           -> root_folder                         -> some files


I have already made the Cyodrake's Gaze for my animation, but I really don't want to have to do it all over again for scenes 6, 7, 31... and so forth.  Is there any way to copy/paste an object into scenes?  Thanks, Nefer007

I have two scenes in a blend file. How do I move a object from one scene to the other? Not between blend files, but within one blend file but two scenes.


Say there is a machine learning algorithm (e.g. classification) that is well known and implemented by the original creators of the algorithm. Yet all you have is the ability to use the algorithm but not see the source code.  Now you want to implement this algorithm and then check if your implementation is correct or not. Since you can't use the same initialization values to the parameters (because you don't have access to the source code of the original implementation) then you can't expect to get exactly the same results. Say that the algorithm gives as outputs probabilities, then your method could give a slightly different result from the original method.  It's true that your implementation could give the correct classification results as with the original implementation but the probabilities could be different.   Given such a scenario, how would you judge that your implementation is correct?  This exact situation happened with a friend whose implementation gave the correct classification results but after all he found a serious bug in his code!  So is there a way to test and validate the implementation of a machine learning algorithm in general? Regardless of type of the algorithm (classification, regression ... etc).  The only problem I can see is not being able to use the same initial values for the parameters. Then maybe there is some kind of a statistical test that can test the results with respect to the initial values of the parameters somehow.

What are some techniques by which we can verify that a current implementation of a machine learning algorithm is correct?  Is using the results of a benchmark dataset is enough?


I am trying to show that   $$\frac{1}{\sqrt{n}}\|A\|_2\leq \|A\|_1\leq \sqrt{n}\|A\|_2.$$ I start with the definition $$ \|A\|_2=\max_{v\neq 0}\frac{\|Av\|_2}{\|v\|_2} .$$ I know that $\forall v\in\mathbb{R}^n$, $\|v\|_2\leq\|v\|_1$. But I do not know how to relate this property to the question at hand. For instance, is $\|Av\|_2\leq\|Av\|_1$?

When reading Golub's "Matrix Computations", I came across a series of norm inequalities. While I could prove a lot of them, this one has me stuck: $$ \frac{1}{\sqrt{m}} ||A||_1 \le ||A||_2 \le \sqrt{n}||A||_1$$ where $A \in \mathbb{R}^{m\times n},$ $||A||_1 = \displaystyle \max_{j \in [1,n]} \sum_{i=1}^m |a_{ij}|$ and $||A||_2 = \max_{||x||=1}||Ax||_2$, where $||Ax||_2$ is the standard Euclidean norm of the vector $Ax$.  I know that $||A||_2 = \max \sigma(A)$ (maximum singular value of $A$), in case that's useful. Help?


Newspapers often put a sentence in large font in the middle of the page to attract attention. For example, see this one:   How is this form of highlighting called? How can I do it? I have a multicolumn document (using the multicol package); If possible, I would like to add a green ruler above and below this text.  Thanks.

Does anyone know a package for ?    Failing that, is anyone interested in writing a command to create one? I'm thinking of something that would have optional and configurable separators above and below (e.g., lines or large quotation marks), and option to float left, right, or center. Ideally the command should print the argument and the pull quote so you do not have to duplicate the text that you want to quote.   To avoid duplicating existing questions, perhaps we should focus on single column documents, so that the pull quote has to be boxed?


Whats the quickest way to generate a list of consecutive numbers in a random order?  i.e. generate a list of numbers from 1 to 100, the list must contain each number once only. The order of the list should be random.  java or c# please.  my pseudocode looks like this, very inefficient.   var list = new list<int>();  for (int i = 1; i <= 100; ++i) {      int x;      repeat {          x = random(1, 100);      until (list.contains(x) == false);      list.add(x);  }

What is the best way to randomize the order of a generic list in C#? I've got a finite set of 75 numbers in a list I would like to assign a random order to, in order to draw them for a lottery type application.


In 8x03, at the end of the episode, Arya      jumps to the Night King and she has an opportunity to kill him.    But I don't understand how she can avoid all the wights and the White Walkers, because there are hundreds of them and they were looking at the same point, at Bran.       The Night King was in font of Bran, so...   I don't understand how she can do it.

In Game of Thrones S08E03 "The Long Night", Arya is a skilled assassin, master of stealth and whatnot.  However, the area around Bran is mostly clear, as shown in earlier scenes, how did they not see or hear that character approaching the Night King? Or did they notice and not warned it (as unlikely as it may sound)?


My App will contain a big database, so how do I insert the data ? I'd like to do that on the PC and then put it in the app, since its a lot of data.  I've seen the posts  /  /  But I don't understand or im not sure its the best way.

If your application requires a database and it comes with built in data, what is the best way to ship that application? Should I:   Precreate the SQLite database and include it in the .apk? Include the SQL commands with the application and have it create the database and insert the data on first use?   The drawbacks I see are:   Possible SQLite version mismatches might cause problems and I currently don't know where the database should go and how to access it. It may take a really long time to create and populate the database on the device.   Any suggestions? Pointers to the documentation regarding any issues would be greatly appreciated.


I am currently writing a small class in C# which will take an image, decompile it down to a byte array, obfuscate the data into a proprietary format (thus making it unreadable), and store said data into a file. The class will also optionally recompile the data, thus decrypting the proprietary format back into an image so that it can be used.  I was just wondering if someone with a better vocabulary than myself could throw a couple of words at me that would mean the same thing as encrypt and decrypt, but as a single word. I understand that there may not be a word for this, because the words hold very different meanings at their base level. However, if someone has anything good I would love to hear it.

I am looking for a word that describes both of these activities, however the word coding does not seem to be suitable.   Likewise with encryption and decryption, cryption does not work well.


My 2007 MacBook (10.6.8) worked perfectly fine with my AirPort Express, until I added a 2010 iMac (10.8.4) to the network.  When I first setup the iMac it connected to the AirPort Express, but not to the internet. The AirPort menubar icon showed an exclamation mark on it. At some point in or after the setup I was prompted to set up my AirPort Express, which had already been configured and working just fine with my MacBook.  I followed the instructions and the AirPort Express restarted. It worked! My iMac was/is now online. However, when I went back to the MacBook it was now showing the same exclamation mark on the AirPort menubar icon that the iMac had initially showed.  I have tried restarting the MacBook, the AirPort Express, and the iMac. I've disabled and enabled the AirPort on the MacBook. After each attempt the MacBook connects to the network and a few seconds later shows the exclamation mark when it fails to receive an IP address.  Wanting to dig into the router settings I opened up AirPort Utility on the iMac but got an error message: "This version of AirPort Utility doesn't support this base station."  Is the problem a compatibility issue between 10.6.8 and 10.8.4? Or 10.8.4 and the older AirPort Express? I'm confused by this since the MacBook did work perfectly fine before, when the iMac did not, and now that the iMac does, the MacBook does not.  Does anyone know what is going on!?

Up until recently I was using my 2007 MacBook perfectly fine with my old AirPort Express. A few days ago I purchased a used mid-2010 iMac which is now running OS X 10.8.3 (something I'm still not too sure I like). When I first brought the iMac home and connected to my network it did so just fine but the AirPort icon in the menu bar showed there was no internet connection, despite the signal being full. I then followed some step-by-step setup which rebooted the AirPort Express and all of a sudden I had internet! Great! …except since then my MacBook has the same problem my iMad had, i.e., it connects to the network just fine but the network icon shows no internet connection :(  I should mention that my MacBook is running OS X 10.6.8. I'm wondering if this is an OS compatibility issue or… Has anyone experienced something similar?


I know that sound waves can be described as pressure waves. Now, let's consider the case of reflection of a sound wave from an open end, as in an organ pipe. My textbook says that, in case of reflection from an open end, the reflected wave suffers a phase change by $π$ radians. In other words, a compression pulse becomes a rarefaction pulse, and a rarefaction pulse becomes a compression pulse. I can't understand (from the explanation given) why that occurs. Does the external medium (that in which the sound wave isn't travelling) has a role to play? I found a slightly similar question  as well as , but I couldn't really understand what's going on.

How can standing waves be produced in an open organ pipe even though both of its ends are open? Can someone explain with more clarity?


How do I move my TempDB Data or Log File(s) from wherever they are now to a different Drive or Folder?

Two things I'd like to know:   how do you safely move tempdb with minimal downtime? how many tempdb files do you need?   Is it 1 file per core? So quad-core = 4 tempdb files, creating three new ones?


I'm trying to do a time series analysis on the total number of deaths (of not just important characters but everyone in general) per epsisode of Game of thrones for a course project. I was wondering if there was a statistic/dataset on total number of deaths per episode per season. I've come to know from Washington Post Dataset (May 2019) that total number is 5863 (latest) and I know per season. But I needed per episode as well. If anyone has a resource, that'd be amazing.  Thanks in advance

While watching Game of Thrones and seeing people being killed left and right, I began to wonder:  Just how many people die per episode (not just major characters but the minor characters as well)?   I'm just wondering about an average, but a list that mentions the number of deaths for each episode would be good too.


How do I generate all possible pairs permutations from a list in Python?  Example:  input = [3, 8, 2] output = ['3-8', '3-2', '8-3', '8-2', '2-3', '2-8']

How do you generate all the permutations of a list in Python, independently of the type of elements in that list?  For example:  permutations([]) []  permutations([1]) [1]  permutations([1, 2]) [1, 2] [2, 1]  permutations([1, 2, 3]) [1, 2, 3] [1, 3, 2] [2, 1, 3] [2, 3, 1] [3, 1, 2] [3, 2, 1]


I have been looking for, and have had trouble finding the following font. Anyone care to help identify? Appreciated.

Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag.


This is the component I'm trying to remove: BU48xx voltage detector VSOF package (attached pic)

I need to transfer a working eight-pin 1/4" (4 mm) chip from the top PCB to the bottom PCB that has a non-working chip. Is there a special soldering tool for such micro soldering? Has anyone tried desoldering/soldering something this small?   Any special technique for this or can it only be done by machine?


I still do not know the answer, so I am looking for hints and tips here. Note that I want to do this with substitution, or at least not by taking derivatives.  Evaluate: (that's a cube root on the numerator)  $$\lim_{x \rightarrow 1}{\frac{\sqrt[3]{x}-1}{\sqrt{x}-1}}$$  The example in the book suggests substituting to make the problem simpler, but I tried using $t = \sqrt{x}-1$ and the numerator also, but I still get a divide by zero in either case.  How do you make an educated guess on what to use for $t$ and substitute?

Evaluate $\lim_{x \to 1} \frac{\sqrt[3]{x} -1}{\sqrt{x} -1}$  I want to solve this limit by employing the strategy of introducing a new variable $t$ in such a way as to make the problem simpler.  I've tried using $t = \sqrt[3]{x} \Rightarrow \lim_{t \to 1} \frac{t -1}{\sqrt{t^3} -1}$ but I can't seem to manipulate the problem in to something simpler.  Can anybody give a hint?


I'm more concerned with the general question of whether any function satisfies the differential equation $f'(x) = f(x+a)$, $a \in \mathbb{R}$. I've tried solving it myself, to no avail.

What could one do to find analytic solutions for $f'(x) = f(x + a)$ for various values of $a$?  I know that $c_1\sin(x + c_2)$ is solution when $a = \frac{1}{2}\pi$, and of course $c_1e^x$ when $a = 0$.  For instance, is there a function satisfying $f'(x) = f(x + 1)$?  What about negative or imaginary $a$?  Is there possibly a generalization?


Under what conditions is \begin{equation*}\frac{\left(n^2-1\right)!}{\left(n!\right)^{n}}\end{equation*} an integer? (It turns out, apparently, that the answer is "precisely when $n$ is non-prime and $\neq 4$". I am interested in whether there is a straightforward proof of this.)

Question: Find all positive integers $n$ such that $(n^2 - 1)!$ is a   multiple of $(n!)^n$.   I can show that the required condition fails if $n$ is a prime, and by direct computation, it also fails for $n=4$. After doing a few small examples by hand, I believe that the required answer is 1 and all composites greater than 4. However, I cannot seem to prove this.  For each prime $p<n$, I tried to count the number of appearances of $p$ on both sides, but I get that I am supposed to compare $n(\lfloor{\frac{n}{p}} \rfloor + \lfloor{\frac{n}{p^2}} \rfloor +\dots)$ against $\lfloor{\frac{n^2-1}{p}} \rfloor + \lfloor{\frac{n^2-1}{p^2}} \rfloor + \dots$, which is not obvious to compare.  Any help will be gretaly appreciated.


I tried to make this scene from blender guro tutorial, but i got problem in my lamp which is to noisy. Is there a solution without increasing my samples render?  Im beginner for this stuff.

I know that this question is a bit old or maybe overdone, but I'm running the latest edition of Blender and when I use the Cycles engine I get really fuzzy results and I can't find a simple, non-compromising solution to the quality.  I don't know exactly what I'm doing wrong here, but I'm sure others share my frustration.  Leaving everything in default settings, I started a new project and switched to the Cycles render.  I duplicated the cube and set colors for two Diffuse BSDF shaders, then went ahead and made walls and a floor all sharing the same diffuse shader.  I made two windows to emit blue light.  The screenshot has gaps between the walls because of the setup:  I'm aware that it's considered very incomplete and many have come to terms with some amount of noise, but is this normal?  Furthermore, with default settings or not, I can't change the amount of noise produced.  Supposedly, using "progressively refine" in the rendering tab should make it refine itself indefinitely, however Cycles only counts to 10 refines and then stops, creating a render which is a pixel-perfect match of the ordinary rendering method when it's completed.  I understand that there are tricks that can be used to reduce noise, but at the cost of extra processing time and usually small quality conflicts, like blurring.  My question essentially boils down to is this Cycles' current limit?


int array[][2] = { {1,0},  {2,2}, {3,4}, {4,17} };  int main() {     /* calculate array size */      printf(" => number of positions to capture : %d", (int)(sizeof(array)/sizeof(array[0])));     func(array);     return 0; } void func(int actu[][2]) {     /* calculate array size */     printf(" => number of positions to capture : %d", (int)(sizeof(actu)/sizeof(actu[0])));  }   Result:   => number of positions to capture : 4 -- inside main  => number of positions to capture : 0 -- inside func -- I believe I should get 4 here too   Size of a same arrray in calling and called function are giving different values. Please, help me to find the issue.

First off, here is some code:  int main()  {     int days[] = {1,2,3,4,5};     int *ptr = days;     printf("%u\n", sizeof(days));     printf("%u\n", sizeof(ptr));      return 0; }   Is there a way to find out the size of the array that ptr is pointing to (instead of just giving its size, which is four bytes on a 32-bit system)?


I've researched loads  but still haven't found my answer. So, my question is would this scenario work? Multi visit visa, trigger the 180 days by an overnight stay in my chosen schengen country. Go back home (non schengen), then back to the same country again for the rest of the 90 allowed days. Then go back home again, for a week, (therefore the first 180 days have ended). Can I then go straight back to our chosen country after this week (with a new visa), for 90 days and not return again until after this second 180 day have ended. Ultimately apart from a week back home we would be in the schengen country for the best part of 6 months in a year and 6 months in our own country. Heres hoping!!

I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation?


I would like to add automatic grammar fix when posting questions or answers.  For example, automatically capitalizes i's, when the letter is used as the word I.  This is something seriously frustrating as someone who has been spending a lot of time editing posts, the majority of which have i's which are not correctly capitalized.  Surely having the i's automatically capitalized where necessary is a simple fix to make?  Please note, that unlike , the request here is not for a spell checker that just mark incorrect words (like some browsers are doing already) but to have it done automatically, without me having to do anything.

It would be nice to see a built-in spell checker into the main text-panel for posts. Every time I post here or Stack Overflow I quickly open up Gmail, paste my post there, and use its spell checker to make sure I didn't make any stupid mistakes. I know other services have these types of features, and it would be nice to see Stack Overflow have one as well.  Agree/disagree?  (BTW, I found two small mistakes for this short post.)  I know I made a comment about this on ChrisF's answer, but I thought that I should also mention it here in the question. I know there are many third-party tools to add spell checker functionality to Stack Overflow. But some (if not many) people out there do not have these tools. They are either at work (like me), or some other place where they using a machine that is not owned by them, or they aren't power users and just don't have these tools installed.  If Stack Exchange becomes used for other non-technical sites, then you will probably have to count on the fact that people are using  or something just as bad. That's why it would just be nice to have a built-in spelling tool. Again, it may not be worth it, but I think it would be interesting to discuss it at least.


I have this query and works. But It seems ugly to me that it needs some optimization since I repeat the same actions over and over again. There must be a better way to merge all of these  SELECT * FROM   (SELECT COUNT(*) AS a    FROM order_item_histories    WHERE order_status_id IN (5, 4, 15)) AS e,   (SELECT COUNT(*) AS b    FROM order_item_histories    WHERE order_status_id IN (6)) AS f,   (SELECT COUNT(*) AS c    FROM order_item_histories    WHERE order_status_id IN (4, 10, 9, 12, 7)) AS g,   (SELECT COUNT(*) AS d    FROM order_item_histories    WHERE order_status_id IN (11, 16, 17, 13)) AS h

I am trying to put together a query will return sales information across multiple date ranges. I was planning to do something like this:  SELECT count(*) AS thirty_day_sales FROM "MySchema"."MyTable" MT WHERE MT.date > now()::date - interval '30 days' UNION SELECT count(*) AS sixty_day_sales FROM "MySchema"."MyTable" MT WHERE MT.date > now()::date - interval '60 days' UNION SELECT count(*) AS ninety_day_sales FROM "MySchema"."MyTable" MT WHERE MT.date > now()::date - interval '90 days'   Is there another, more efficient way to do this that doesn't use UNION? I'd prefer not to have to repeat the SELECT and WHERE lines over and over, as the actual criteria are a lot longer and move convoluted than this, with multiple tables joined together.


I don't know what to do, because I have older phone HTC Desire 526G and updates are just not pushed and I believe that they will not push them ever, but out there there is so many vulnerabilities for the OS which I'm running currently 4.4.2 Kitkat.  Buying a new phone is not an option for me right now. So my question here is; can I somehow install Lineage OS on that device? What is the worst it can happen?

I own a MicroMax A100. I want to install the latest version of a different ROM (Samsung or Nexus).  Is it possible? If so, can you tell me how?  If not, can I install a ROM made for a different device, but from the same manufacturer? For example, could I install a ROM for the MicroMax A110, which is the successor of A100?


Chat rooms can be associated with meta sites, as discussed, for example, here:  (In this post you can notice that there were some recent changes concerning where the rooms associated with metas are displayed.) So I wanted to test whether it is possible to create a new room associated to a meta site. To my surprise, this was possible only for some sites. For example, if I start to type "math", several metas are offered. When I start to type "history", I am only offered main sites. See the screenshots below. (Or you can test this for yourself in the .) This experiment suggests that only the meta sites, for which at least one room already exists, are offered. I have listed metas which had a chatroom  (at the time of posting that question).  another explanation was suggested, namely that meta sites are not offered for beta sites. For this reason I have included a third screenshot showing that - at the moment - meta is offered in this dialogue neither for Information Security nor for Seasoned Advice. (However, for Server Fault both meta and main are in the list.) So the distinction between beta sites and graduated sites is not sufficient to explain this.  Why only some metas are offered in this dialogue as possible room parents? Is it on purpose?   I do not think it is a big deal. But I can imagine a situation where associating room with meta might be useful. For example, imagine that community around some SE site wants to have two separate rooms: A "main chat room" for general discussion about the subject of this site and a "meta chat room" for various "janitorial" tasks (like closing, reopening, retagging, editing, flagging and advice related to this - which is somewhat separate from the the subject of the site, more closely related to maintenance and moderating of the site). It is my understanding that at least one room associated with a site, be it a main site or meta, is kept alive, even if there was no activity for 14 days. (And  seems to confirm this.) So the advantage of this arrangement would be that the "janitorial" room would not be frozen even if there were some periods of inactivity. (Assuming it is the only room associated with that particular meta site.) Perhaps you can think  of some other scenarios when having meta as a parent room might be useful. However, this is not that important for my main question - I am simply asking why the dialogue for room creation behaves in the way described above and whether it is .   Here are the screenshots:     EDIT: Very recently the only room associated with Meta Mathoverflow has been . It seems that this changed the list of rooms offered in this dialogue - Meta Mathoverflow is not offered there anymore. (You can notice that in the screenshot which I took less than an hour ago, Meta Mathoverflow was one of the possibilities.)

When I try to create a new  room from , and type "meta" in the "select a site" box, I see only 8 child meta sites. Any specific reason for this?  Update:  I just noted  (pointed out by ). The conclusion of the experiment there was:        This experiment suggests that only the meta sites, for which at least   one room already exists, are offered.   ...the distinction between beta sites and graduated sites is not sufficient to explain this.      So, if I'm reading it correctly, it is currently impossible to create a room hosted on those child metas which do not already have an existing meta room (smells like a bug!)? Or is there a way to bypass this restriction somehow?  I can think of several legitimate reasons as to why a site may choose to keep their main chat rooms and meta chat rooms separate. Killing off that freedom of choice, and that too non-uniformly, isn't a good idea. If this really is a  rather than  (for a good cause), then it should be fixed!


The "Background" panel in "System Settings/Appearance", allows to select the background color of the desktop, solid or with a gradient.  There, the "Pick a color" window allows to choice a color from a standard palette, or a custom color.  Whenever you select a custom color, a corresponding sample is shown under the standard palette.  It happens, however, that there is no obvious way to delete a custom color, so the line of samples grows accordingly.  So there is a problem when you want to delete a number of custom colors.  The data of these colors, which are associated with the user, are supposedly in the home directory, but I've not find any reference to them.  Can you suggest me  where to look?

I added color on the gnome-terminal as in the picture and now I want to delete the custom colors added    I want to have the colors as in this picture


I wrote a code with template copy constructor to get a better understanding of the concept as I am new to it but the following code fails to compile  #include <iostream> #include <vector>  using namespace std;  template <typename T> class Grid { public:     explicit Grid(size_t inWidth = kDefaultWidth, size_t inHeight = kDefaultHeight);     virtual ~Grid();      template <typename E>     Grid(const Grid<T>& src);      static const size_t kDefaultWidth = 10;     static const size_t kDefaultHeight = 10;     std::vector<std::vector<T>> mCells;     size_t mWidth, mHeight; };  template <typename T> template <typename E> Grid<T>::Grid(const Grid<T>& src) {     cout << "Copy constructor working " << endl;  }  int main() {     Grid<double> myDoubleGrid;     Grid<double> newDoubleGrid(myDoubleGrid);     return 0; }   On compiling the above code in visual studio following error appears:-  ERROR:-     Severity   Code    Description Project File    Line    Suppression State   Error   C2558   class 'Grid': no copy constructor available or copy constructor is declared 'explicit'     I have tried to replace the argument's template with E and It shows more errors (strange ones)  template <typename T> template <typename E> Grid<T>::Grid(const Grid<E>& src) {     cout << "Copy constructor working " << endl;  }   Errors:     Severity   Code    Description Project File    Line    Suppression State   Error   LNK2019 unresolved external symbol "public: __thiscall Grid::Grid(unsigned int,unsigned int)" (??0?$Grid@N@@QAE@II@Z) referenced in function _main            Error  LNK1120 2 unresolved externals            Error  LNK2019 unresolved external symbol "public: virtual __thiscall Grid::~Grid(void)" (??1?$Grid@N@@UAE@XZ) referenced in function "public: virtual void * __thiscall Grid::`scalar deleting destructor'(unsigned int)" (??_G?$Grid@N@@UAEPAXI@Z)

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


If I have drawn a line-art diagram that is 250px x 350px on a screen with 92.56 PPI (Dell U2414H - 1920 x 1080, 23.8 inch diagonal) - I'm confused as to why, when this image is transferred into Photoshop (CS6), its detected dimensions are 3.486" x 4.875".   Should it not be 250/92.56 = 2.7" wide?  Ultimately - I am trying to meet the requirements of a publisher which states the maximum width of an image must be 3.5" - I simply do not know how to calculate whether or not my image falls below this.

I have two cameras, a 6mpix Panasonic FZ8, and 14mpix Canon A2200.  When I compare shots from two cameras, one of differences I notice is dpi number that camera reports in JPG info:   FZ8 reports dpi=72 A2200 reports dpi=180   What physical meaning can these numbers have? I am at loss for guesses.    I am fairly familiar with notion of dpi in scanning and printing. I can calculate density of pixels on the sensor of the camera. But then, the linear density of pixels on the sensor will be hundreds times larger than number above. So what, if anything, does it mean?


The first program works, when the variable var is defined outside the function f. The value 232 is outputted successfully. In the second program, var is again defined outside the function f, but I get an error saying that var is not defined when the print statement in the function is run. Why does the first program work, but the second program doesn't work?  First program:  var = 232 def f():     print (var)  f()   The second program:  var = 232 def f():     print (var)     var +=1  f()   The output of the first program is expected - it outputs the value 232. The output of the second program should be 232, and it then increments var, but a local variable error occurs at the print statement at line 3.

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


I installed 12.04 LTS 64 bits from a USB drive, but I can't seem to boot from the HDD. I have a single partition, with no other OSes. I need to plug in the USB drive for the PC to boot Ubuntu. Is my install OK?

I had Ubuntu 12.04 Beta installed on my computer. When 12.04 was finally released, I made a bootable USB Flash Drive using Startup Disk Creator.  Then I decided to check if this drive works properly and to reinstall the system on my desktop. I must add, my desktop behaves a bit strange when it comes to bootable USB's, it recognizes them as HDD.  In BIOS I changed priority of boot so USB Flash Drive (recognized as HDD) was first. Successfully booted, I installed Ubuntu. Everything worked fine, but...  Now I cannot boot from my real HDD. Every time I want to boot, I put the USB Flash Drive into my computer, boot, safely remove it and everything works.  What do I need to do to repair boot?


I have an array and it has repeating items. So I trying to delete item if it repeats. For example:  $links:    string(35) "/mjr/semba-tower/outline/index.html"   [1]=>   string(38) "/mjr/mc-futsukaichi/outline/index.html"   [2]=>   string(31) "/mjr/chihaya/outline/index.html"   [3]=>   string(35) "/mjr/semba-tower/outline/index.html"   As you see 2 semba-towers in the array and I want to delete one of if.  I tried this, but output returns 0 item.  $output = [];         foreach(array_count_values($links) as $value => $count)         {             if($count == 1)             {                 $output[] = $value;             }         }          var_dump($output);    Any other way to fix this problem?

How can I remove duplicate values from an array in PHP?


Adding page numbers in QGIS Layouts can be done with the [% @layout_page %] expression. In Reports, however, the [% @layout_page %] expression always remains "1"  How do we insert the page number in a Report?

I don't really get the behaviour of QGIS new reports (3.X) ...  I inserted an attribute table in a report. this table is spanning over several pages. I would like to create a page footer with the page numbering (current page and total amount of pages).  That seems quite trivial ... but ... can QGIS reports do that ?  I'm not in the case of an atlas.


Are there matrices such that $AB=I$ and $BA \neq I$ ?   $A$ and $B$ are square matrices

If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix.


Let $\alpha > 1$ and $M \geq 0$. Suppose $f: \mathbb{R} \longrightarrow \mathbb{R}$ satisfies $|f(x)-f(y)|\leq M|x-y|^\alpha$ for all $x, y\in \mathbb{R}$.  How can we prove that $f$ is a constant function? I don't even know where to start.

Suppose $f:(a,b) \to \mathbb{R} $ satisfy $|f(x) - f(y) | \le M |x-y|^\alpha$ for some  $\alpha >1$ and all $x,y \in (a,b) $. Prove that $f$ is constant on $(a,b)$.   I'm not sure which theorem should I look to prove this question. Can you guys give me a bit of hint? First of all how to prove some function $f(x)$ is constant on $(a,b)$? Just show $f'(x) = 0$?


How can I reuse/access my Ubuntu 14.04 Operating System(OS) to get my important files.  My Hard disk drive(HDD) is partitioned into two.I had previously installed both Windows 7 and Ubuntu 14.04 (on each partition) on my IBM T60 Thinkpad. The Boot-screen that always showed up was that of Ubuntu and I would select either "Ubuntu" or "Windows 7" from there. They(OS) were working very well except Windows 7 had viruses so I had to re-install it. I managed to re-install it but now on booting, it doesn't display any Boot-screen but that of windows 7.   On the hard disk drive(HDD) the partition for Ubuntu is still present.And it occupies all the partition though windows 7 can't show it anywhere.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


What font is used in this document ? It looks like CM but CM is lighter than this font?

Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag.


I've been always using classic disk partitioning and Clonezilla images of selected partitions for fast recovery in case of a catastrophic disk failure. I'm now testing LVM on a new system. It also uses whole disk encryption so the whole volume group is encrypted.  Q1: Can volume snapshots be used for the recovery in the way I've been using Clonezilla?  Q2: If Q1 is yes, does it still apply if the physical partition is encrypted?

Setting up LVM Snapshot as a backup/restore point in ubuntu. Why? Well, as I see it, with all the great usefulness of Linux, its biggest drawback is with its mixed up way of installing apps. All the dlls go to one directory. All the configuration files to another. And the binaries are also put in a bunch. Yes, Windows works the same way more or less, but with the nature of system/server software installed on Linux, being that most of the software installed is only about 95% mature at any given time, messing up your system twice a month is very probable.. Of course, we can backup the system before and after each installation, but that takes a million years. System backups (as oppose to just data/files backup) requires you to turn off you computer and use some form of bootable live CD and a backup media. And, if the drive is more than 15% full, it might take a long time to do the backup, even with modern hardware. So, how can this be done?


From what I know, the rule to distribute exponents is like:  $$(a b)^x = a^x b^x$$  Thus, if $a = \sqrt 2$ and $b = \sqrt 3$, $ab = \sqrt 6$.  However, the imaginary unit $i = \sqrt{-1}$ has a different behavior, because if I take $a = -2$, $b = -3$ and $x = 1/2$:  $${[(-2) (-3)]}^{1/2} = (-2)^{1/2} (-3)^{1/2} = \sqrt{-2} \sqrt{-3} = i\sqrt 2 i \sqrt 3 = - \sqrt 6$$  Although, before I learned complex numbers, I thought,  $${[(-2) (-3)]}^{1/2} = [6]^{1/2} = \sqrt 6$$  What am I making wrong here and which is the right answer?

I understand why $e^{i\pi} = -1$and as a result  $e^{i2\pi}=\left(e^{i\pi}\right)^2=1.$ These results can be confirmed using Euler's formula  But why does $e^{i\pi/3}\neq -1$ as we can write it $(e^{i\pi})^{1/3}$ and as such $(-1)^{1/3}$ the cubic root of $-1$ is $-1$ itself.  Yet using Euler's formula we get $e^{i\pi/3}=\frac{1}{2}+i\frac{\sqrt 3}{2}$.


Let us assume that $n \in \mathbb{N}$. It is quite easy to prove that:  $$\int_{0}^{1} x^{n-1} \log (1-x) \, {\rm d}x = - \frac{\mathcal{H}_n}{n}$$  since if we use the series representation of $\mathcal{H}_m$ we have that:  \begin{equation} \mathcal{H}_m = \sum_{k=1}^{\infty} \left [ \frac{1}{k} - \frac{1}{m+k} \right ] \tag{1}\end{equation}  and it follows that our initial integral , call that $\mathcal{J}$ ,   \begin{align*} \mathcal{J} &=\int_{0}^{1} x^m \log(1-x) \, {\rm d}x \\   &= - \int_{0}^{1}x^m \sum_{n=1}^{\infty} \frac{x^n}{n} \, {\rm d}x \\   &= - \sum_{n=1}^{\infty} \frac{1}{n} \int_{0}^{1}x^{m+n} \, {\rm d}x\\   &= - \sum_{n=1}^{\infty} \frac{1}{n \left ( n+m+1 \right )}\\   &= - \sum_{n=1}^{\infty}\left[\frac{1}{(m+1)n} - \frac{1}{(m+1) \left ( m+n+1 \right )} \right]\\   &= - \frac{1}{m+1} \sum_{n=1}^{\infty} \left [ \frac{1}{n} - \frac{1}{n+m+1} \right ]\\  &\overset{(1)}{=} - \frac{\mathcal{H}_{m+1}}{m+1} \end{align*}  Now let us raise the exponent of $\log (1-x)$ by one. That is we now consider the integral  $$\int_{0}^{1} x^{n-1} \log^2 (1-x) \, {\rm d}x = \frac{1}{n} \left [ \mathcal{H}_n^2 + \mathcal{H}_n^{(2)} \right ]$$  The derivation is pretty much easy. What can we say for the integral   $$\mathcal{J}(n, m) =\int_{0}^{1} x^{n-1} \log^m (1-x) \, {\rm d}x $$  I have a conjecture that states that it will involve a sum of $\mathcal{H}_n$ raised to the corresponding power of the log and a sum of $\mathcal{H}_n^{(m)}$. However, I am unable to make any progress for the general case. Diffing the Beta won't help us here. This is what I've done for the $m=2$ case. I just diffed the Beta twice. Any clever approach?  Also what we can say for the integral:  $$\mathcal{J}^*(n, m) =\int_{0}^{1} x^{n-1} \log^m (1+x) \, {\rm d}x $$  Well, one last thing one should note is that both integrals actually connect to . Maybe we could use the Taylor series expansion of $\log^m (1 \pm x)$ and reduce the problem to Stirling numbers. I am not that familiar though.

Let $n \in \mathbb{N}$. We know that:  $$\int_0^1 x^n \log(1-x) \, {\rm d}x = - \frac{\mathcal{H}_{n+1}}{n+1}$$  Now, let $m , n \in \mathbb{N}$. What can we say about the integral  $$\int_0^1 x^n \log^m (1-x) \, {\rm d}x$$  For starters we know that $\displaystyle \log^m (1-x)=m! \sum_{k=m}^{\infty} (-1)^k \frac{s(k, m)}{k!} x^k$ where $s(k, m)$ are the .   Thus  \begin{align*} \int_{0}^{1} x^n \log^m (1-x) \, {\rm d}x &=m! \int_{0}^{1}x^n \sum_{k=m}^{\infty} (-1)^k \frac{s(k, m)}{k!} x^k  \\   &= m! \sum_{k=m}^{\infty} (-1)^k \frac{s(k, m)}{m!} \int_{0}^{1}x^{n+m} \, {\rm d}x\\   &= m! \sum_{k=m}^{\infty} (-1)^k \frac{s(k, m)}{m!} \frac{1}{m+n+1} \end{align*}  Can we simplify? I know that Striling numbers are related to the Harmonic number but I don't remember all identities.


is there any force on a tennis ball causing it to go forward after it leaves the person hands. Any help is much appreciated

A body continues in its state of motion unless a force is applied to it. But how does an object stay in motion in the first place? A force must have caused it to move right?


Image :   (sorry I don't have reps to post the image directly)  This is a square made up by 4 equal 90 degrees sectors which 1 side of it is equal to 7cm(actually the radius)  I found the area of these:  1 sector = 38.5   Square - 1 sector = 10.5   1 sector - (square - 1 sector) = 28  I got this question from a friend of mine I tried many ways to do this also tried making equations considering algebra (namig x,  y,  z)   I don't have any idea to solve that now :(  Also I made my account here specially for this question   THANKS IN ADVANCE

The centers of four circles are at the vertices of a square of sidelength 100m. Each circle has the radius of 100m. Which is the area of their intersection?


What does this error mean ?  /dev/mapper/ubuntu--vg-root: clean   It was shown during startup but the system booted fine.  Do I have to do anything?

After I upgraded my Ubuntu from 14.04 to 16.04, I am getting a weird line on my screen each time I power on my laptop:    /dev/sda5: clean, 956436/30277632 files, 37421826/123093120 blocks   What does this line mean?  I worry about the meaning of the numbers, because the first number says that some files were cleaned, and the second one says that some files were blocks...   Nothing special or complicated, just for general understanding.


I'm a bit familarized with conditional sentences. But the following sentences with 'should' and 'happen to' are quite confusing too me. They are:   If it should rain, I will stay at home. 2.If it should happen to rain, I'll stay at home   If it happens to rain, I'll stay at home.    What are the meaings of those sentences ? Do they all mean the same ? Thank you a lot in Advance for your answer.

What is the difference in the meaning of following sentences (I'm asking for detailed anlaysis of these sentences)   If it rains, I will stay at home. If it should rain, I will stay at home. If it should happen to rain, I will stay at home If it happens to rain, I will stay at home.  Can I say 'there is no difference in the meaning among 2 ,3 and 4 sentences ? There is no difference in the meaning and usage among 'should', 'happen to' or should happen to' together. Do they all mean 'by chance' ?   Again , i would like to know if the following sentences are grammatically correct or not:  1.If she should happen to read the newspaper, she would see your article.  2.If they should agree to come ,we would be delighted.  Source :perfect English grammar.com in Advanced conditionals Explained (pdf )


Here is a code from the Domino 8 designer help to get database categories.  The condition "if(cat != "") always return true though database category is empty or non-empty. What is catch?  import lotus.domino.*; public class JavaAgent extends AgentBase {   public void NotesMain() {     try {       Session session = getSession();       AgentContext agentContext =            session.getAgentContext();       // (Your code goes here)        Database db = agentContext.getCurrentDatabase();       String title = db.getTitle();       String cat = db.getCategories();       if (cat != "")//This condition does not work         System.out.println("Database \"" +         title + "\" has the categories: " + cat);       else         System.out.println("Database \"" +         title + "\" has no categories");     } catch(Exception e) {       e.printStackTrace();     }   } }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Uplink and Downlink speeds, other statistics etc without third party software

how to display the actual network traffic (wireless) in a terminal?  Additionally: Is it possible to add this info to the chart of top?


It's accepted fact that pictures move, and that portraits talk.  However, why is it that the subject of a portrait can be in only one frame at a time?  Also, what happens, if a new portrait is made? As soon as it is complete, does the subject disappear (to maintain that there is only one subject across all the frames)?  On an extra(and possibly useless) note, I remember that Harry once got a Chocolate Frog card of Dumbledore, and Dumbledore shortly walked out of it. Ron commented something along the lines of, "Can't expect him to hang around all the time." So, do Chocolate Frogs also share their subjects with portaits? I understand that photographs, atleast, seem exempt from this logic. No idea about celebrity posters(like those of the Cannons and Krum) either.  Lastly, what is the point of having multiple portraits if they are almost always empty? Doesn't it defeat the point of having a magical portrait? I would find it offensive if I went to the trouble of having a portrait put up, only for the subject to promptly walk out.  The following questions touch upon a similar topic, but focus on the magic behind the sentience of the subjects, rather than their availability:

We learn very quickly that the headmaster's study has paintings of all former headmasters and headmistresses on the wall.  Eventually we learn that they can travel to at least one other painting of themselves.  When Dumbledore died, it seemed like his portrait magically appeared on the wall.  (Although I recall reading that Harry put Snape's picture up himself, can anyone reconcile those?)  Is there just one other painting of each headmaster that they can visit?  I get the idea this is the case or else there would be empty frames of headmaster paintings all over, as it seems they can only be in one frame at a time.    If it is just the pair, how does the second come to be? Does it just magically appear like Dumbledore's portrait did after he died?  Where might it appear?  There wasn't a second of Dumbledore mentioned when his main picture appeared after he died, but iirc the OoP ended up with the other end of him.  If it's multiple, how are they linked? An enchantment?  How close do they have to be in appearance? Could any magical child paint a stick figure of Albus Dumbledore and have their mommy make it a connection to the Headmaster's study? (It is things like that that make me think it must be just the two, tied portraits.)


Is there a search command or a section where I can manage all my files and folders I shared? I know there is 'Shared with me' section but this only shows items from other people.

In Dropbox there is a place you can see all the shared items in your account (i.e., all the items you have granted others access to).  Is there a similar feature in Google Drive?  I'm not only trying to find items that are shared with other "named people", but also documents that are shared on a "anyone with link can view / edit" or "public on the internet" basis.   Franck's  seemed to work back in 2013, but Google Drive's interface has changed quite a bit since, and I'm struggling to be able to perform the same task with the new interface. I wonder if anyone knows how to do it in the new interface.


How do I handle resolution change in OpenGL and SDL2, in combination?  Let´s assume I have a GUI window with a fixed position, so it will be on the right corner of the window, and after resolution change it will be at the same position, just resized due to the resolution change. How do I handle the resolution change?  How do I apply these changes to my game physics? For example, with collision boxes, do I need to define some variable like resolutionRatio and multiply it against the collision rectangle dimensions?

I'm unsure as to what people prefer when it comes to HUDs, and scaling them. What would you say is the best practice when it comes to sizing the HUD? I'm thinking there's really two options: Scale up, or use the same area (in pixels) to display it on a higher resolution.  The problems I see with each are with scaling, I may have a huge blurry mess in the corner, but if I don't, it could be hard to see from a distance. Any guidance?


I am trying to write a simple C program that takes the input from user in metres and prints the output in kilometres, yards and miles rounded to 4 decimal places. I have used this 1 meter = 0.001 kilometers = 1.094 yards = 0.0006215 miles When I write this, I get the output as intended: #include <stdio.h> int main() {    int m;    float km, y, mi;    scanf("%d",&m);    km=(m*0.001);    y=(m*1.094);    mi=(m*0.0006215);    printf("%.4f\n%.4f\n%.4f",km,y,mi);    return 0; }  Output: 0.1000 109.4000 0.0622 But, when I write this I get the third output wrong: #include <stdio.h> int main() {    int m;    scanf("%d",&m);    printf("%.4f\n%.4f\n%.4f",(m*0.001),(m*1.094),(m*0.0006215));    return 0; }  Output: 0.1000 109.4000 0.0621 Can you please help me find the reason for this difference?  Edit-1 here I gave input 100. float y=100*0.0006215; printf("%f",y);  gave output 0.062150 and this printf("%f",100*0.0006215);  also gave output 0.062150  Edit-2 float y=100*0.0006215; printf("%.4f",y);  gave output 0.0622 while: printf("%.4f",100*0.0006215);  gave output 0.0621 whereas in Edit-1 both displayed the same output.

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


I am modifying a WordPress theme, but the problem is every time I edit my CSS file via FileZilla and upload it to the server, the CSS file doesn't get updated immediately after browser refresh and it's very frustrating.  I get the idea that the CSS ver tag is helping browser not to cache old CSS files, but for the temporary purpose, I would like to disable it.  Can you guys give me a hint, how the code of style.css?ver=1.0.0 tag command might look like? So that I can reverse engineer it and modify it my self or remove it completely.

I know that I can use the following function to remove the version from all .css and .js files:  add_filter( 'style_loader_src', 'sdt_remove_ver_css_js', 9999 ); add_filter( 'script_loader_src', 'sdt_remove_ver_css_js', 9999 ); function sdt_remove_ver_css_js( $src ) {     if ( strpos( $src, 'ver=' ) )         $src = remove_query_arg( 'ver', $src );     return $src; }   But I have some files, for instance style.css, in the case of which I want to add a version in the following way:  function css_versioning() {     wp_enqueue_style( 'style',         get_stylesheet_directory_uri() . '/style.css' ,         false,         filemtime( get_stylesheet_directory() . '/style.css' ),         'all' ); }   But the previous function removes also this version. So the question is how to make the two work together?


I have a list of cells that contain 1 of 12 values. I have 4 different colors that I want the the cell filled depending on the cell value. How do I do this?  We are running Excel Professional 2010 Del

Possible Duplicate:          I have a spreadsheet where I have cell within a row that will contain specific text via data validation. So for instance a cell could contain the text "Due in 7 Days", "Past Due", or "Closed".  I want the row color to change depending on the text that appears in the cell. So if the text "Past Due" appears in the cell I want that entire row to turn red, if "Due In 7 Days" appears the row should turn yellow, and if "Closed" the row would turn gray.  How can I do that?


I'm implementing a DFS algorithm and I want to create a list of dictionaries. But I found that if I use [dict()] * n, I got unexpected result.  I'm not sure what is the difference between "[dict()] * n" and a "for loop with .append(dict())".  Any hint is appreciated.  def DFS1(nums, level, target, dp):     if level == len(nums):         if target == 0:             return 1         else:             return 0      if target in dp[level]:         return dp[level][target]      cnt1 = DFS1(nums, level + 1, target + nums[level], dp)     cnt2 = DFS1(nums, level + 1, target - nums[level], dp)     dp[level][target] = cnt1 + cnt2     return cnt1 + cnt2   test code is:   nums = [1,1,1,1,1] n = len(nums) target = -3 #dp = [dict()] * n   #<== This does not work as expected dp = [] for i in range(0, n):     dp.append(dict())  resCnt = DFS1(nums, 0, target, dp) print(resCnt)

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


All regular* distributions of $\mathcal{D}'(\mathbb{R}^n)$ can be characterised as $L^1_{loc}(\mathbb{R}^n)$. Is there a similar characterisation of the regular distributions of $\mathcal{S}'(\mathbb{R}^n)$?    I often found, that all allgebraically bounded $f \in L^1_{loc}(\mathbb{R}^n)$, i.e. $\exists C>0, N>0:\ |f(t)|\le C(1+|t|)^N$, give regular tempered distributions, but for example this does not contain $\chi_{[-1,1]} \frac{1}{\sqrt{|t|}}\in L^1(\mathbb{R}^n)$, which should also be a regular tempered distribution? On the other hand, it should be "smaller" than $L^1_{loc}(\mathbb{R}^n)$ as $e^t$ won't give a regular tempered distribution.    (*) A tempered distribution $T\in \mathcal{S}'(\mathbb{R}^n)$ is called regular in this context, if it can be represented by an (ordinary) function $f\in L^1_{loc}(\mathbb{R}^n)$, i.e. $$\exists f\in L^1_{loc}(\mathbb{R}^n):\quad T(\phi)=\int_{\mathbb{R}} f \phi\ dx \ \qquad\forall \phi \in \mathcal{S}(\mathbb{R}^n)$$

Today's problem originates in  conversation with Willie Wong about the Fourier transform of a Gaussian function   $$g_{\sigma}(x)=e^{-\sigma \lvert x \rvert^2},\quad x \in \mathbb{R}^n;$$  where $\sigma$ is a complex parameter. When $\Re (\sigma) \ge 0$, $g_\sigma$ is a tempered distribution$^{[1]}$ and so it is Fourier transformable.   On the contrary, it appears obvious that if $\Re(\sigma) <0$ then $g_\sigma$ is not tempered.      Question 1. What is the fastest way to prove this?    My guess is that one should exploit the fact that the pairing  $$\int_{\mathbb{R}^n} g_\sigma(x)\varphi(x)\, dx$$  makes no sense for some $\varphi \in \mathcal{S}(\mathbb{R}^n)$. But is it enough? I am afraid that this argument is incomplete.     Question 2. More generally, is there some characterization of tempered functions, that is, functions which belong to the space $L^1_{\text{loc}}(\mathbb{R})\cap \mathcal{S}'(\mathbb{R})$?    The only tempered functions that I know are polynomially growing functions. By this I mean the functions of the form $Pu$, where $P$ is a polynomial and $u \in L^p(\mathbb{R}^n)$ for some $p\in[1, \infty]$.      Question 3. Is it true that all tempered functions are polynomially  growing functions?     $^{[1]}$ The definition of tempered distribution I refer to is the following.   A distribution $T \in \mathcal{D}'(\mathbb{R}^n)$ is called tempered if for every sequence $\varphi_n \in \mathcal{D}(\mathbb{R}^n)$ such that $\varphi_n \to 0$ in the Schwartz class sense, it happens that $\langle T, \varphi_n \rangle \to 0$. If this is the case then $T$ uniquely extends to a continuous linear functional on $\mathcal{S}(\mathbb{R}^n)$ and we write $T \in \mathcal{S}'(\mathbb{R}^n)$.


Extending the question asked in  , we do instantiate an Interface while initialize it with implemented class.  My question is why in the first place, we are instantiate it with the Interface? Why can't I directly instantiate it with implemented class? For eg. :   Doc mydoc = new SimpleDoc();   Where Doc is interface and SimpleDoc is implementing it. What is the problem with      SimpleDoc mydoc = new SimpleDoc(); Where this will fail?

I have seen this mentioned a few times and I am not clear on what it means. When and why would you do this?   I know what interfaces do, but the fact I am not clear on this makes me think I am missing out on using them correctly.   Is it just so if you were to do:  IInterface classRef = new ObjectWhatever()   You could use any class that implements IInterface? When would you need to do that? The only thing I can think of is if you have a method and you are unsure of what object will be passed except for it implementing IInterface. I cannot think how often you would need to do that.   Also, how could you write a method that takes in an object that implements an interface? Is that possible?


I have both Windows and Ubuntu on my machine with dual boot. Windows is on the SSD, and Ubuntu is on a normal hard drive. I've tried the most common solution online, which is booting from a Windows repair USB stick and typing bootrec.exe /fixmbr. But that doesn't work. I've read somewhere that that only works for adjacent Windows and Linux partitions. So, how should I uninstall Ubuntu without any traces?

I have a Win/Ubuntu 11.10 dual-boot setup, where I am running the OSes on separate partitions of my laptop HDD. I assume the best method of uninstalling is 'simply' a matter of deleting the Ubuntu partitions -once I've made sure control is given to the Windows bootloader instead of grub after POST.  The question is: How do I do that?  Stuff I've tried:  I tried the boot-repair CD (), but that was a bit beyond my abilities to figure out if I could do it with that tool :/.  I also tried EasyBCD (). It couldn't identify my ext3 partitions, let alone change the bootloader.  Lastly, I tried installing startup-manager in Ubuntu, and using that to set the Win7 bootloader as default. But upon restart, it still loads grub.


Calculate $$\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}{\frac{\sin^{2014}x}{\sin^{2014}x + \cos^{2014}x}}dx$$ Integration by parts and variable substitutes don't seem to lead anywhere. Help would be appreciated.  EDIT: a more general version of this question is answered here:

Evaluate the integral $$\int^{\frac{\pi}{2}}_0 \frac{\sin^3x}{\sin^3x+\cos^3x}\, \mathrm dx.$$  How can i evaluate this one? Didn't find any clever substitute and integration by parts doesn't lead anywhere (I think).  Any guidelines please?


I am developing an app that for the most part presents large static textual information. I intend the app to be offline so no fetching of data from server. As already discussed on many posts I have following options as per my understanding:     Storing it in XML resource file  text file in assets folder SQLite database   Though initially I decided to go with XML, but for features like proper sorting, filtering and indexing of data SQLite is handy. I read ,  and  about trade-offs between various methods. Now, if I am storing data in SQLite:     From where should I feed data? Won't I have to first store it in a text file or Strings.xml?  If yes, then I would need to parse XML(may be multiple files) to insert it in database tables   and then reading tables to display data in Views, leading to redundancy (as I could directly populate views after parsing XML) and also taking double the size for data(XML and database). Am sure there is nothing in android studio like "feeding database from some resource while generating apk and not bundle up that resource as a part of apk". So my question essentially is how to effectively use SQLite for large static text data? Thanks (sorry if my description is bit lengthy than necessary)    EDIT: Also there will be no data manipulation while the app is being used.

If your application requires a database and it comes with built in data, what is the best way to ship that application? Should I:   Precreate the SQLite database and include it in the .apk? Include the SQL commands with the application and have it create the database and insert the data on first use?   The drawbacks I see are:   Possible SQLite version mismatches might cause problems and I currently don't know where the database should go and how to access it. It may take a really long time to create and populate the database on the device.   Any suggestions? Pointers to the documentation regarding any issues would be greatly appreciated.


I've accidentally deleted a  project directory from my Ubuntu with rm -rf.  is it possible to restore them somehow?

Are there any tools, methods, incantations to recover recently deleted files on Ubuntu?  If it makes any difference, I want to recover a  2.x database file. But would be better to have a method/tool that works on any kind of file.


I realize these would probably be neologisms or maybe trademarks, but are there some obvious example "words" to use that contain a number or symbol? (eg 0123456789!@#$%^&*()  For the purpose of this discussion, lets exclude hyphenated words.

Is ' (the apostrophe) the only character which is not part of the English alphabet that can appear in the correct spelling of an English word?


I have heared that there is connection between number theory and physics. I specially ask that:          Can anyone give a concrete example which shows this connection?   I want to see an example which is related to (integral) quadratic forms or theta series.          Let $f$ to be a quadratic form; i.e a homogeneous polynomial of degree two (in any number of variables), for example $4x_1^2 + 3x_1x_2 + 5x_1x_3 - 8x_3^2$. Also let's assume that all of the co-efficeints of $f$ are integral.    Now let's fix a  (integral) quadratic form $f$ in $m$ variables, and let $n$ varies in $\mathbb{N}$; let's define:   $$  N(n)  :=  N(f,n)  =  N\big(f(x_1, ..., x_m),n\big)  =  \#  \{(x_1, ..., x_m) \in \mathbb{Z}^m : f(x_1, ..., x_m)=n \}  ;  $$ note that $N(n)$ is the number of integral solutions to the equation $f=n$; now by a  associated to the quadratic form $f$ we mean the following:   $$  \Theta(q)  :=  \Theta_f(q)  =  \sum_{n\in \mathbb{N}_0}N(n)q^n  =\sum_{(x_1, ..., x_m) \in \mathbb{Z}^m}q^{f(x_1, ..., x_m)}  ;  $$   also if we assume that $q=e^{2\pi i z}$;  then there is theorem which states that $\Theta_f(q)$ is a modular form in $z$.      I have asked my question  again.

As a Graduate Mathematics student, my interest lies in Number theory. I am curious to know if Number theory has any connections or applications to physics. I have never even heard of any applications of Number theory to physics. I have heard Applications of linear algebra and analysis to many branches of physics, but not number theory.  Waiting forward in receiving interesting answers!