How to increase Heap size of JVM
How can I increase the JVM memory?
Are threads implemented as processes on Linux? I'm going through , Advanced Linux Programming by Mark Mitchell, Jeffrey Oldham, and Alex Samuel. It's from 2001, so a bit old. But I find it quite good anyhow.  However, I got to a point when it diverges from what my Linux produces in the shell output. On page 92 (116 in the viewer), the chapter 4.5 GNU/Linux Thread Implementation begins with the paragraph containing this statement:     The implementation of POSIX threads on GNU/Linux differs from the   thread implementation on many other UNIX-like systems in an important   way: on GNU/Linux, threads are implemented as processes.   This seems like a key point and is later illustrated with a C code. The output in the book is:  main thread pid is 14608 child thread pid is 14610   And in my Ubuntu 16.04 it is:  main thread pid is 3615 child thread pid is 3615   ps output supports this.  I guess something must have changed between 2001 and now.  The next subchapter on the next page, 4.5.1 Signal Handling, builds up on the previous statement:     The behavior of the interaction between signals and threads varies   from one UNIX-like system to another. In GNU/Linux, the behavior is   dictated by the fact that threads are implemented as processes.   And it looks like this will be even more important later on in the book. Could someone explain what's going on here?  I've seen this one , but it doesn't help much. I'm confused.  This is the C code:  #include &lt;pthread.h&gt; #include &lt;stdio.h&gt; #include &lt;unistd.h&gt;  void* thread_function (void* arg) {     fprintf (stderr, "child thread pid is %d\n", (int) getpid ());     /* Spin forever. */     while (1);     return NULL; }  int main () {     pthread_t thread;     fprintf (stderr, "main thread pid is %d\n", (int) getpid ());     pthread_create (&amp;thread, NULL, &amp;thread_function, NULL);     /* Spin forever. */     while (1);     return 0; } Interpolation of multibeam bathymetry using ArcGIS Desktop? I'm trying to make a 3D map with multi-beam bathymetry (65536 features, xyz), but it seems that the interpolation methods are too rigid. I need to smooth the data so it looks more natural and realistic.   Which parameters do I have to vary so I can get this? The equivalence of sample correlation and R statistic for simple linear regression Post-hoc tests after Kruskal-Wallis: Dunn's test or Bonferroni corrected Mann-Whitney tests? I have some non-Gaussian distributed variable and I need to check if there are significant differences between the values of this variable in 5 different groups.  I have performed Kruskal-Wallis one-way analysis of variance (which came up significant) and after that I had to check which groups were significantly different. Since the groups are kind of sorted (the values of the variable in the first group are supposed to be lower than the values of the variable in the second group which are supposed to be lower than the values of the variable in the third group and so on) I only performed 4 tests:  Group 1 vs Group 2 Group 2 vs Group 3 Group 3 vs Group 4 Group 4 vs Group 5   I have performed this analysis with two different methods. I started by using Dunn's Multiple Comparison Test but nothing came up significant. On the other hand if I use Mann-Whitney test and correct for the number of tests (4) using Bonferroni, 3 tests come up significant.  What does it mean? Which results should I trust? Let $A \in Mat_{n \times n}(F)$ a matrix which satisfies $A^n=0$ and $A^{n-1} \ne 0$ for some positive integer $n$. Let $v \in F^n$ be such that $A^{n-1}v \ne 0$.  Prove that $\{v, Av, A^2v,...,A^{n-1}v\}$ is a basis for $F^n$.     So, from definition of $A$, I know that $A^iv \ne 0$ for all $0\le i \le n-1$. I know I need to prove the set is linearly independent and span $F^n$ to prove it's a basis, but I just don't know how. Some icons are correct, and some are whack. Turns out it's not just the hot questions list, but the whole icon set. How can I find the program I'm hiding in bash Say I have PATH="home/bob/bin:/usr/bin".  I am writing a bash script /home/bob/bin/foo that will do some munging and then call /usr/bin/foo.  Of course I want to be able to use this script on different systems which have different path structures.  In practice the real foo might be in many different places, so I want to just find it from the PATH.  My new foo script is on my path too, so I can't just call foo, that will result in a recursive call.  Is there an easy way of doing this in a bash script? (Other than looping through elements of PATH and doing the search manually?) The Software Center in Ubuntu 16.04 (Gnome Software) shows only part of the packages available. While e.g. apt list qtcreator correctly lists the corresponding package a search in Software Center finds nothing.  Is there something misconfigured? I upgraded from 15.10. Until now I have used the old Ubuntu Software Center which worked fine. Prove that all 2x2 orthogonal matrices can be expressed as Rotation or Reflection Origin —  Elementary Number Theory — Jones — p35 — Exercise 2.17 — For which primes $p$ is $p^2 + 2$ also prime? Only for $p = 3$. If $p \neq 3$ then $p = 3q ± 1$ for some integer $q$, so $p^2 + 2 = 9q^2 ± 6q + 3$ is divisible by $3$, and is therefore composite. (1) The key here looks like writing $p = 3q ± 1$. Where does this hail from? I know $3q - 1, 3q, 3q + 1$ are consecutive. $p$ is prime therefore $p \neq 3q$? (2) How can you prefigure $p = 3$ is the only solution? Does $p^2 + 2$ expose this? On an exam, I can't calculate $p^2 + 2$ for many primes $p$ with a computer — or make random conjectures. In An Introduction to Statistical Learning (James et al.), in section 3.7 exercise 5, it states that the formula for $\hat{\beta}_1$ assuming linear regression without an intercept is  $$\hat{\beta}_1 = \dfrac{\displaystyle\sum\limits_{i=1}^{n}x_iy_i}{\displaystyle \sum\limits_{i=1}^{n}x_i^2}\text{,}$$ where $\hat{\beta}_0 = \bar{y}-\hat{\beta}_1\bar{x}$ and $\hat{\beta}_1 = \dfrac{\displaystyle S_{xy}}{S_{xx}}$ are the usual estimates under OLS for simple linear regression ($S_{xy} = \displaystyle\sum\limits_{i=1}^{n}(x_i - \bar{x})(y_i - \bar{y})$).  This is not the actual exercise; I am merely wondering how to derive the equation. Without using matrix algebra, how do I derive it?   My attempt: with $\hat{\beta}_0 = 0$, we have $\hat{\beta}_1 = \dfrac{\bar{y}}{\bar{x}} = \dfrac{S_{xy}}{S_{xx}}$.  After some algebra, it can be shown that $\displaystyle S_{xy} = \sum\limits_{i=1}^{n}x_i^2 - n\bar{x}\bar{y}$ and $\displaystyle S_{xx} = \sum\limits_{i=1}^{n}x_i^2 - n\bar{x}^2$. From here, I'm stuck. I have problems transferring binary programs to a micro-controller prototype board when using ubuntu/kubuntu to mount the board via usb. With MacOS and Windows there are no problems. I have found the writing from Ubuntu definitely changes the written file. I suspect that the write caching is the problem. How can I disable it, or what else might be the problem. Why an abstract class implementing an interface can miss the declaration/implementation of one of the interface's methods? A curious thing happens in Java when you use an abstract class to implement an interface: some of the interface's methods can be completely missing (i.e. neither an abstract declaration or an actual implementation is present), but the compiler does not complain.  For example, given the interface:  public interface IAnything {   void m1();   void m2();   void m3(); }   the following abstract class gets merrily compiled without a warning or an error:  public abstract class AbstractThing implements IAnything {   public void m1() {}   public void m3() {} }   Can you explain why? How to do vlookup and fill down (like in Excel) in R? Windows 7 Automatically Connecting To Unsecured Wireless Networks On Startup Most of the questions on this topic related to folks connecting to somebody else's wireless network when their own was available and could remedy the situation by going to their connections and unchecking the "connect automatically" box.  See this: "  " as an example.  In my situation, I've noticed that Win 7 will automatically connect to any unsecured wifi network - even if I have never connected to it in the past.  If I am traveling and boot Win 7, it will start and connect to what appears to be the best signaled unsecured network without prompting me for confirmation (note: in the above link, "Naveen" seems to have same problem).  Obviously, that is a security concern to me.  Further, when I open "Network and Sharing" and "Manage wireless networks"  the network is not displayed (probably because I labelled it a public network).  Again, these are new, never connected with before, wireless networks.  I always promptly disconnect from them but don't want to have to be on constant guard for an auto connection to a malicious network.  This began about a month ago, as I recall, Win 7 did not behave like this in the past, I didn't monkey with wifi settings, and don't use a 3rd party connection manager.  I did have to download some internet security certificates for army website access but I don't think that should mess with network settings.  Any ideas how I can tell Win7 cease automatically connecting to networks or, at least, to prompt me for a confirmation before connecting? "Open With" dialog ignores my selection I am running Windows 7 x64. I have a file type that I want to associate with Microsoft Access 2003.  I right-click on the file and select Open With->Choose Default program. In the "Open With" dialog, I select the browse button. I choose Program Files (x86)\Microsoft Office\Office11\msaccess.exe and press "Open".  I end up back at the "Open With" dialog, but nothing has changed. Access is not listed as a program to use to open the file with. The original program (Adobe Acrobat) that is associated with this program is still selected.  Any tips on getting this association to work? Creating polygon from hole in QGIS? What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? Provide an easily discoverable way to get the full URL to an answer I have some difficulties with a task in algebra. I guess it's trivial and really easy but I can't figure out how to solve it.  I have a set $G$ and a binary operation on it, let it be $\circ$. I have that the operation is associative and that the equations $a\circ x = b$ and $x\circ a = b$ have unique solutions. I have to prove that $(G, \circ)$ is a group.  I already have that the operation is binary and associative, so I have to prove that there is unique identity element and unique inverse element and it will come from the equations, but how exactly?