Commit 0f6b13c7 authored by Matthieu Schaller's avatar Matthieu Schaller
Browse files

Use the threaded version of FFTW to speed-up the PM part of the code.

parent daa00858
......@@ -588,7 +588,7 @@ AH_VERBATIM([__STDC_FORMAT_MACROS],
# Check for FFTW. We test for this in the standard directories by default,
# and only disable if using --with-fftw=no or --without-fftw. When a value
# is given GSL must be found.
# is given FFTW must be found.
have_fftw="no"
AC_ARG_WITH([fftw],
[AS_HELP_STRING([--with-fftw=PATH],
......@@ -599,10 +599,10 @@ AC_ARG_WITH([fftw],
)
if test "x$with_fftw" != "xno"; then
if test "x$with_fftw" != "xyes" -a "x$with_fftw" != "xtest" -a "x$with_fftw" != "x"; then
FFTW_LIBS="-L$with_fftw/lib -lfftw3"
FFTW_LIBS="-L$with_fftw/lib -lfftw3_threads -lfftw3"
FFTW_INCS="-I$with_fftw/include"
else
FFTW_LIBS="-lfftw3"
FFTW_LIBS="-lfftw3_threads -lfftw3"
FFTW_INCS=""
fi
# FFTW is not specified, so just check if we have it.
......
......@@ -801,7 +801,7 @@ int main(int argc, char *argv[]) {
/* Initialise the long-range gravity mesh */
if (with_self_gravity && periodic) {
#ifdef HAVE_FFTW
pm_mesh_init(&mesh, &gravity_properties, s.dim);
pm_mesh_init(&mesh, &gravity_properties, s.dim, nr_threads);
#else
/* Need the FFTW library if periodic and self gravity. */
error(
......
......@@ -596,9 +596,10 @@ void pm_mesh_interpolate_forces(const struct pm_mesh* mesh,
* @param mesh The #pm_mesh to initialise.
* @param props The propoerties of the gravity scheme.
* @param dim The (comoving) side-lengths of the simulation volume.
* @param nr_threads The number of threads on this MPI rank.
*/
void pm_mesh_init(struct pm_mesh* mesh, const struct gravity_props* props,
double dim[3]) {
double dim[3], int nr_threads) {
#ifdef HAVE_FFTW
......@@ -608,6 +609,7 @@ void pm_mesh_init(struct pm_mesh* mesh, const struct gravity_props* props,
const int N = props->mesh_size;
const double box_size = dim[0];
mesh->nr_threads = nr_threads;
mesh->periodic = 1;
mesh->N = N;
mesh->dim[0] = dim[0];
......@@ -622,6 +624,12 @@ void pm_mesh_init(struct pm_mesh* mesh, const struct gravity_props* props,
if (2. * mesh->r_cut_max > box_size)
error("Mesh too small or r_cut_max too big for this box size");
/* Initialise the thread-parallel FFTW version */
if (N >= 64) {
fftw_init_threads();
fftw_plan_with_nthreads(nr_threads);
}
/* Allocate the memory for the combined density and potential array */
mesh->potential = (double*)fftw_malloc(sizeof(double) * N * N * N);
if (mesh->potential == NULL)
......@@ -660,6 +668,8 @@ void pm_mesh_init_no_mesh(struct pm_mesh* mesh, double dim[3]) {
*/
void pm_mesh_clean(struct pm_mesh* mesh) {
fftw_cleanup_threads();
if (mesh->potential) free(mesh->potential);
mesh->potential = 0;
}
......@@ -692,6 +702,12 @@ void pm_mesh_struct_restore(struct pm_mesh* mesh, FILE* stream) {
#ifdef HAVE_FFTW
const int N = mesh->N;
/* Initialise the thread-parallel FFTW version */
if (N >= 64) {
fftw_init_threads();
fftw_plan_with_nthreads(mesh->nr_threads);
}
/* Allocate the memory for the combined density and potential array */
mesh->potential = (double*)fftw_malloc(sizeof(double) * N * N * N);
if (mesh->potential == NULL)
......
......@@ -39,6 +39,9 @@ struct pm_mesh {
/*! Is the calculation using periodic BCs? */
int periodic;
/*! The number of threads used by the FFTW library */
int nr_threads;
/*! Side-length of the mesh */
int N;
......@@ -65,7 +68,7 @@ struct pm_mesh {
};
void pm_mesh_init(struct pm_mesh *mesh, const struct gravity_props *props,
double dim[3]);
double dim[3], int nr_threads);
void pm_mesh_init_no_mesh(struct pm_mesh *mesh, double dim[3]);
void pm_mesh_compute_potential(struct pm_mesh *mesh, const struct space *s,
struct threadpool *tp, int verbose);
......
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