On 2/12/2009 1:44 PM, Sturla Molden wrote:
Here is an example of SciPy's ckdtree.pyx modified to use OpenMP.
It seems I managed to post an errorneous C file. :(
S.M.
/*
* Parallel query for faster kd-tree searches on SMP computers.
* This function will release the GIL around the lengthy query
loop and
* use OpenMP for multithreading.
*
* OpenMP is supported on GCC (since version 4.2) and MS Visual
C++ 2005
* and later. Mingw builds of GCC supports OpenMP through a pthread
* layer (pthreadGC2.dll).
*
* Compile with -fopenmp and link -lgomp -lpthread on GCC.
*
* Written by Sturla Molden, Univ. Oslo, Jan. 24 2009
*
*
* This code is released to public domain.
*
*/
#include <Python.h>
#include <omp.h>
typedef void (*queryfun_t)(void *self, double *result_distances,
int*result_indices, double*x, int k, double eps, double p, double
distance_upper_bound);
void parallel_query(queryfun_t query, int nthreads, int niter, void *self,
double*result_distances,
int *result_indices, double*x, int k, int m, double eps, double p,
double distance_upper_bound)
{
int c;
/* allow the number of threads to be specified */
if (nthreads == 0) {
Py_BEGIN_ALLOW_THREADS {
#pragma omp parallel for private(c) schedule(guided)
for (c=0; c<niter; c++) {
(*query)(self, result_distances + c*k,
result_indices + c*k, x + c*m, k,
eps, p, distance_upper_bound);
}
} Py_END_ALLOW_THREADS
} else {
/* parallel queries with GIL released */
Py_BEGIN_ALLOW_THREADS {
#pragma omp parallel for private(c) schedule(guided)
num_threads(nthreads)
for (c=0; c<niter; c++) {
(*query)(self, result_distances + c*k,
result_indices + c*k, x + c*m, k,
eps, p, distance_upper_bound);
}
} Py_END_ALLOW_THREADS
}
}
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