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Re: memory leak in GTS/IntersectionDetector?

 



mspieg wrote:
Hi All,
I'm playing with some characteristic based advection schemes in Dolfin (0.9.0) which require a large number of discrete Function evals. This seems to be leading to a large memory leak as the process grows considerably in size with every time-step. I've put together a small (badly written) program that demonstrates the problem which I've tried to isolate just to IntersectionDetector (and the underlying GTS). I suspect the problem is in GTS, but thought I would start with Dolfin support. Any thoughts/help greatly appreciated...


I recall that quite some time ago some memory leaks were fixed in the DOLFIN GTS interface, but there remained some GTS problems. Have you run valgrind?

Garth

Cheers
marc
----------------------------------------------------
Marc Spiegelman
Lamont-Doherty Earth Observatory
Dept. of Applied Physics/Applied Math
Columbia University
http://www.ldeo.columbia.edu/~mspieg
tel: 845 704 2323 (SkypeIn)
----------------------------------------------------


p.s. Some basic info
Dolfin (0.9.0) hg development version (ported to PETSc-3.0.0)
GTS (0.7.6) built from source
MacOSX 10.4.11
g++ i686-apple-darwin8-g++-4.0.1 (GCC) 4.0.1 (Apple Computer, Inc. build 5370)
boost 1.33.1

test code
----------------------------------------------
// Copyright (C) 2009 Marc Spiegelman
// Licensed under the GNU LGPL Version 2.1.
//
// First added:  2008-10-08
// Last changed:  5 Feb 2009 17:16:07
//
// Heavily modified from dolfin/demo/mesh/intersection code
// Program to demonstrated memory leak from large number of random GTS intersectionDetector tests
// uses boost uniform random number generator for fun
// // Note: if you just continually test the point {0.5, 0.5} (comment out the random number generator) // the number of intersected cells is 6 rather than 1 and the memory leak is much more pronounced //
#include <dolfin.h>
#include <boost/random.hpp>

using namespace dolfin;

typedef boost::mt19937 base_generator_type;

int main()
{
  // Create square mesh
  unsigned int N = 64;
  UnitSquare mesh(N, N);

  //create IntersectionDetector
  IntersectionDetector ID(mesh);
// set initial point
  double x[2] = {0.5, 0.5 };
  Point p(2,x);

  //initialize cell Array
  std::vector<dolfin::uint> cells;
  std::vector<dolfin::uint>::iterator cellIterator;

  //setup boost uniform variate random number generators
  base_generator_type  generator(42u);
  boost::uniform_real<> uni_dist(0,1);
boost::variate_generator<base_generator_type&, boost::uniform_real<> > uni(generator, uni_dist); dolfin::uint k, k_max = N*N*5000, k_print = 100;
  dolfin::uint n_cells, n_cells_print=2;

  //calculate a random intersection k_max times
  for (k = 0; k < k_max; k++ ) {
    ID.intersection(p, cells);
    n_cells = cells.size();

//print out information if number of cells in intersection matches n_cells_print (or every k_print grid_sweep)
    if (n_cells >= n_cells_print || k%(N*N*k_print) == 0 ) {
printf("k=%d, p=[%f, %f], NCells=%d: ", k, p.x(), p.y(), (int) cells.size()) ; for (cellIterator = cells.begin(); cellIterator < cells.end(); cellIterator++) {
printf("%d ",*cellIterator);
      }
      printf("\n");
    }

    // get new random point (comment out to really blow up)
    p[0] = uni();
    p[1] = uni();

// clear cells array (cells grows with every test otherwise, not sure if this generates a memory leak) cells.clear(); }
  return(0);
}














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