Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / java-1.2.8 / javamem.m

diff --git a/octave_packages/java-1.2.8/javamem.m b/octave_packages/java-1.2.8/javamem.m
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+## Copyright (C) 2010 Philip Nienhuis, <prnienhuis@users.sf.net>
+## 
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} javamem
+## @deftypefnx {Function File} [@var{jmem}] = javamem
+## Show current memory status of the Java virtual machine (JVM)
+## & run garbage collector.
+##
+## When no return argument is given the info is echoed to the screen.
+## Otherwise, output cell array @var{jmem} contains Maximum, Total,
+## and Free memory (in bytes).
+##
+## All Java-based routines are run in the JVM's shared memory pool,
+## a dedicated and separate part of memory claimed by the JVM from
+## your computer's total memory (which comprises physical RAM and
+## virtual memory / swap space on hard disk).
+##
+## The maximum available memory can be set using the file java.opts
+## (in the same subdirectory where javaaddpath.m lives, see 
+## "which javaaddpath". Usually that is: @*
+## [/usr]/share/octave/packages/java-<version>.
+##
+## java.opts is a plain text file, one option per line. The
+## default initial memory size and default maximum memory size (which
+## are both system dependent) can be overridden like so: @*
+## -Xms64m @*
+## -Xmx512m @*
+## (in megabytes in this example.)
+## You can adapt these values to your own requirements if your system
+## has limited available physical memory or when you get Java memory
+## errors.
+##
+## "Total memory" is what the operating system has currently assigned
+## to the JVM and depends on actual and active memory usage.
+## "Free memory" is self-explanatory. During operation of Java-based
+## octave functions the amounts of Total and Free memory will vary,
+## due to Java's own cleaning up and your operating system's memory
+## management.
+##
+## @end deftypefn
+
+## Author: Philip Nienhuis
+## Created: 2010-03-25
+## Updates: 
+## 2010-03-26 Changed name to javamem & indentation to double spaces
+## 2010-08-25 Corrected text on java memory assignments
+## 2010-09-05 Further overhauled help text
+
+function [ j_mem ] = javamem ()
+
+  rt = java_invoke ('java.lang.Runtime', 'getRuntime');
+  rt.gc;
+  jmem = cell (3, 1);
+  jmem{1} = rt.maxMemory ().doubleValue ();
+  jmem{2} = rt.totalMemory ().doubleValue ();
+  jmem{3} = rt.freeMemory ().doubleValue ();
+
+  if (nargout < 1)
+    printf ("\nJava virtual machine (JVM) memory info:\n");
+    printf ("Maximum available memory:        %5d MiB;\n", jmem{1} / 1024 / 1024);
+    printf ("   (...running garbage collector...)\n");
+    printf ("OK, current status:\n");
+    printf ("Total memory in virtual machine: %5d MiB;\n", jmem{2} / 1024 / 1024);
+    printf ("Free memory in virtual machine:  %5d MiB;\n", jmem{3} / 1024 / 1024);
+    printf ("%d CPUs available.\n", rt.availableProcessors ());
+  else
+    j_mem = jmem;
+  endif
+
+endfunction