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Tue, Sep 17, 15:11

pm_periodic.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <float.h>
#include <mpi.h>
/*! \file pm_periodic.c
* \brief routines for periodic PM-force computation
*/
#ifdef PMGRID
#ifdef PERIODIC
#ifdef NOTYPEPREFIXFFTW
#include <rfftw_mpi.h>
#else
#ifdef DOUBLEPRECISION_FFTW
#include <drfftw_mpi.h> /* double precision FFTW */
#else
#include <srfftw_mpi.h>
#endif
#endif
#include "allvars.h"
#include "proto.h"
#define PMGRID2 (2*(PMGRID/2 + 1))
static rfftwnd_mpi_plan fft_forward_plan, fft_inverse_plan;
static int slab_to_task[PMGRID];
static int *slabs_per_task;
static int *first_slab_of_task;
static int *meshmin_list, *meshmax_list;
static int slabstart_x, nslab_x, slabstart_y, nslab_y, smallest_slab;
static int fftsize, maxfftsize;
static fftw_real *rhogrid, *forcegrid, *workspace;
static fftw_complex *fft_of_rhogrid;
static FLOAT to_slab_fac;
/*! This routines generates the FFTW-plans to carry out the parallel FFTs
* later on. Some auxiliary variables are also initialized.
*/
void pm_init_periodic(void)
{
int i;
int slab_to_task_local[PMGRID];
All.Asmth[0] = ASMTH * All.BoxSize / PMGRID;
All.Rcut[0] = RCUT * All.Asmth[0];
/* Set up the FFTW plan files. */
fft_forward_plan = rfftw3d_mpi_create_plan(MPI_COMM_WORLD, PMGRID, PMGRID, PMGRID,
FFTW_REAL_TO_COMPLEX, FFTW_ESTIMATE | FFTW_IN_PLACE);
fft_inverse_plan = rfftw3d_mpi_create_plan(MPI_COMM_WORLD, PMGRID, PMGRID, PMGRID,
FFTW_COMPLEX_TO_REAL, FFTW_ESTIMATE | FFTW_IN_PLACE);
/* Workspace out the ranges on each processor. */
rfftwnd_mpi_local_sizes(fft_forward_plan, &nslab_x, &slabstart_x, &nslab_y, &slabstart_y, &fftsize);
for(i = 0; i < PMGRID; i++)
slab_to_task_local[i] = 0;
for(i = 0; i < nslab_x; i++)
slab_to_task_local[slabstart_x + i] = ThisTask;
MPI_Allreduce(slab_to_task_local, slab_to_task, PMGRID, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
MPI_Allreduce(&nslab_x, &smallest_slab, 1, MPI_INT, MPI_MIN, MPI_COMM_WORLD);
slabs_per_task = malloc(NTask * sizeof(int));
MPI_Allgather(&nslab_x, 1, MPI_INT, slabs_per_task, 1, MPI_INT, MPI_COMM_WORLD);
if(ThisTask == 0)
{
for(i = 0; i < NTask; i++)
printf("Task=%d FFT-Slabs=%d\n", i, slabs_per_task[i]);
}
first_slab_of_task = malloc(NTask * sizeof(int));
MPI_Allgather(&slabstart_x, 1, MPI_INT, first_slab_of_task, 1, MPI_INT, MPI_COMM_WORLD);
meshmin_list = malloc(3 * NTask * sizeof(int));
meshmax_list = malloc(3 * NTask * sizeof(int));
to_slab_fac = PMGRID / All.BoxSize;
MPI_Allreduce(&fftsize, &maxfftsize, 1, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
}
/*! This function allocates the memory neeed to compute the long-range PM
* force. Three fields are used, one to hold the density (and its FFT, and
* then the real-space potential), one to hold the force field obtained by
* finite differencing, and finally a workspace field, which is used both as
* workspace for the parallel FFT, and as buffer for the communication
* algorithm used in the force computation.
*/
void pm_init_periodic_allocate(int dimprod)
{
static int first_alloc = 1;
int dimprodmax;
double bytes_tot = 0;
size_t bytes;
MPI_Allreduce(&dimprod, &dimprodmax, 1, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
/* allocate the memory to hold the FFT fields */
if(!(rhogrid = (fftw_real *) malloc(bytes = fftsize * sizeof(fftw_real))))
{
printf("failed to allocate memory for `FFT-rhogrid' (%g MB).\n", bytes / (1024.0 * 1024.0));
endrun(1);
}
bytes_tot += bytes;
if(!(forcegrid = (fftw_real *) malloc(bytes = imax(fftsize, dimprodmax) * sizeof(fftw_real))))
{
printf("failed to allocate memory for `FFT-forcegrid' (%g MB).\n", bytes / (1024.0 * 1024.0));
endrun(1);
}
bytes_tot += bytes;
if(!(workspace = (fftw_real *) malloc(bytes = imax(maxfftsize, dimprodmax) * sizeof(fftw_real))))
{
printf("failed to allocate memory for `FFT-workspace' (%g MB).\n", bytes / (1024.0 * 1024.0));
endrun(1);
}
bytes_tot += bytes;
if(first_alloc == 1)
{
first_alloc = 0;
if(ThisTask == 0)
printf("\nAllocated %g MByte for FFT data.\n\n", bytes_tot / (1024.0 * 1024.0));
}
fft_of_rhogrid = (fftw_complex *) & rhogrid[0];
}
/*! This routine frees the space allocated for the parallel FFT algorithm.
*/
void pm_init_periodic_free(void)
{
/* allocate the memory to hold the FFT fields */
free(workspace);
free(forcegrid);
free(rhogrid);
}
/*! Calculates the long-range periodic force given the particle positions
* using the PM method. The force is Gaussian filtered with Asmth, given in
* mesh-cell units. We carry out a CIC charge assignment, and compute the
* potenial by Fourier transform methods. The potential is finite differenced
* using a 4-point finite differencing formula, and the forces are
* interpolated tri-linearly to the particle positions. The CIC kernel is
* deconvolved. Note that the particle distribution is not in the slab
* decomposition that is used for the FFT. Instead, overlapping patches
* between local domains and FFT slabs are communicated as needed.
*/
void pmforce_periodic(void)
{
double k2, kx, ky, kz, smth;
double dx, dy, dz;
double fx, fy, fz, ff;
double asmth2, fac, acc_dim;
int i, j, slab, level, sendTask, recvTask;
int x, y, z, xl, yl, zl, xr, yr, zr, xll, yll, zll, xrr, yrr, zrr, ip, dim;
int slab_x, slab_y, slab_z;
int slab_xx, slab_yy, slab_zz;
int meshmin[3], meshmax[3], sendmin, sendmax, recvmin, recvmax;
int rep, ncont, cont_sendmin[2], cont_sendmax[2], cont_recvmin[2], cont_recvmax[2];
int dimx, dimy, dimz, recv_dimx, recv_dimy, recv_dimz;
MPI_Status status;
if(ThisTask == 0)
{
printf("Starting periodic PM calculation.\n");
fflush(stdout);
}
force_treefree();
asmth2 = (2 * M_PI) * All.Asmth[0] / All.BoxSize;
asmth2 *= asmth2;
fac = All.G / (M_PI * All.BoxSize); /* to get potential */
fac *= 1 / (2 * All.BoxSize / PMGRID); /* for finite differencing */
/* first, establish the extension of the local patch in the PMGRID */
for(j = 0; j < 3; j++)
{
meshmin[j] = PMGRID;
meshmax[j] = 0;
}
for(i = 0; i < NumPart; i++)
{
for(j = 0; j < 3; j++)
{
slab = to_slab_fac * P[i].Pos[j];
if(slab >= PMGRID)
slab = PMGRID - 1;
if(slab < meshmin[j])
meshmin[j] = slab;
if(slab > meshmax[j])
meshmax[j] = slab;
}
}
MPI_Allgather(meshmin, 3, MPI_INT, meshmin_list, 3, MPI_INT, MPI_COMM_WORLD);
MPI_Allgather(meshmax, 3, MPI_INT, meshmax_list, 3, MPI_INT, MPI_COMM_WORLD);
dimx = meshmax[0] - meshmin[0] + 2;
dimy = meshmax[1] - meshmin[1] + 2;
dimz = meshmax[2] - meshmin[2] + 2;
pm_init_periodic_allocate((dimx + 4) * (dimy + 4) * (dimz + 4));
for(i = 0; i < dimx * dimy * dimz; i++)
workspace[i] = 0;
for(i = 0; i < NumPart; i++)
{
slab_x = to_slab_fac * P[i].Pos[0];
if(slab_x >= PMGRID)
slab_x = PMGRID - 1;
dx = to_slab_fac * P[i].Pos[0] - slab_x;
slab_x -= meshmin[0];
slab_xx = slab_x + 1;
slab_y = to_slab_fac * P[i].Pos[1];
if(slab_y >= PMGRID)
slab_y = PMGRID - 1;
dy = to_slab_fac * P[i].Pos[1] - slab_y;
slab_y -= meshmin[1];
slab_yy = slab_y + 1;
slab_z = to_slab_fac * P[i].Pos[2];
if(slab_z >= PMGRID)
slab_z = PMGRID - 1;
dz = to_slab_fac * P[i].Pos[2] - slab_z;
slab_z -= meshmin[2];
slab_zz = slab_z + 1;
workspace[(slab_x * dimy + slab_y) * dimz + slab_z] += P[i].Mass * (1.0 - dx) * (1.0 - dy) * (1.0 - dz);
workspace[(slab_x * dimy + slab_yy) * dimz + slab_z] += P[i].Mass * (1.0 - dx) * dy * (1.0 - dz);
workspace[(slab_x * dimy + slab_y) * dimz + slab_zz] += P[i].Mass * (1.0 - dx) * (1.0 - dy) * dz;
workspace[(slab_x * dimy + slab_yy) * dimz + slab_zz] += P[i].Mass * (1.0 - dx) * dy * dz;
workspace[(slab_xx * dimy + slab_y) * dimz + slab_z] += P[i].Mass * (dx) * (1.0 - dy) * (1.0 - dz);
workspace[(slab_xx * dimy + slab_yy) * dimz + slab_z] += P[i].Mass * (dx) * dy * (1.0 - dz);
workspace[(slab_xx * dimy + slab_y) * dimz + slab_zz] += P[i].Mass * (dx) * (1.0 - dy) * dz;
workspace[(slab_xx * dimy + slab_yy) * dimz + slab_zz] += P[i].Mass * (dx) * dy * dz;
}
for(i = 0; i < fftsize; i++) /* clear local density field */
rhogrid[i] = 0;
for(level = 0; level < (1 << PTask); level++) /* note: for level=0, target is the same task */
{
sendTask = ThisTask;
recvTask = ThisTask ^ level;
if(recvTask < NTask)
{
/* check how much we have to send */
sendmin = 2 * PMGRID;
sendmax = -1;
for(slab_x = meshmin[0]; slab_x < meshmax[0] + 2; slab_x++)
if(slab_to_task[slab_x % PMGRID] == recvTask)
{
if(slab_x < sendmin)
sendmin = slab_x;
if(slab_x > sendmax)
sendmax = slab_x;
}
if(sendmax == -1)
sendmin = 0;
/* check how much we have to receive */
recvmin = 2 * PMGRID;
recvmax = -1;
for(slab_x = meshmin_list[3 * recvTask]; slab_x < meshmax_list[3 * recvTask] + 2; slab_x++)
if(slab_to_task[slab_x % PMGRID] == sendTask)
{
if(slab_x < recvmin)
recvmin = slab_x;
if(slab_x > recvmax)
recvmax = slab_x;
}
if(recvmax == -1)
recvmin = 0;
if((recvmax - recvmin) >= 0 || (sendmax - sendmin) >= 0) /* ok, we have a contribution to the slab */
{
recv_dimx = meshmax_list[3 * recvTask + 0] - meshmin_list[3 * recvTask + 0] + 2;
recv_dimy = meshmax_list[3 * recvTask + 1] - meshmin_list[3 * recvTask + 1] + 2;
recv_dimz = meshmax_list[3 * recvTask + 2] - meshmin_list[3 * recvTask + 2] + 2;
if(level > 0)
{
MPI_Sendrecv(workspace + (sendmin - meshmin[0]) * dimy * dimz,
(sendmax - sendmin + 1) * dimy * dimz * sizeof(fftw_real), MPI_BYTE, recvTask,
TAG_PERIODIC_A, forcegrid,
(recvmax - recvmin + 1) * recv_dimy * recv_dimz * sizeof(fftw_real), MPI_BYTE,
recvTask, TAG_PERIODIC_A, MPI_COMM_WORLD, &status);
}
else
{
memcpy(forcegrid, workspace + (sendmin - meshmin[0]) * dimy * dimz,
(sendmax - sendmin + 1) * dimy * dimz * sizeof(fftw_real));
}
for(slab_x = recvmin; slab_x <= recvmax; slab_x++)
{
slab_xx = (slab_x % PMGRID) - first_slab_of_task[ThisTask];
if(slab_xx >= 0 && slab_xx < slabs_per_task[ThisTask])
{
for(slab_y = meshmin_list[3 * recvTask + 1];
slab_y <= meshmax_list[3 * recvTask + 1] + 1; slab_y++)
{
slab_yy = slab_y;
if(slab_yy >= PMGRID)
slab_yy -= PMGRID;
for(slab_z = meshmin_list[3 * recvTask + 2];
slab_z <= meshmax_list[3 * recvTask + 2] + 1; slab_z++)
{
slab_zz = slab_z;
if(slab_zz >= PMGRID)
slab_zz -= PMGRID;
rhogrid[PMGRID * PMGRID2 * slab_xx + PMGRID2 * slab_yy + slab_zz] +=
forcegrid[((slab_x - recvmin) * recv_dimy +
(slab_y - meshmin_list[3 * recvTask + 1])) * recv_dimz +
(slab_z - meshmin_list[3 * recvTask + 2])];
}
}
}
}
}
}
}
/* Do the FFT of the density field */
rfftwnd_mpi(fft_forward_plan, 1, rhogrid, workspace, FFTW_TRANSPOSED_ORDER);
/* multiply with Green's function for the potential */
for(y = slabstart_y; y < slabstart_y + nslab_y; y++)
for(x = 0; x < PMGRID; x++)
for(z = 0; z < PMGRID / 2 + 1; z++)
{
if(x > PMGRID / 2)
kx = x - PMGRID;
else
kx = x;
if(y > PMGRID / 2)
ky = y - PMGRID;
else
ky = y;
if(z > PMGRID / 2)
kz = z - PMGRID;
else
kz = z;
k2 = kx * kx + ky * ky + kz * kz;
if(k2 > 0)
{
smth = -exp(-k2 * asmth2) / k2;
/* do deconvolution */
fx = fy = fz = 1;
if(kx != 0)
{
fx = (M_PI * kx) / PMGRID;
fx = sin(fx) / fx;
}
if(ky != 0)
{
fy = (M_PI * ky) / PMGRID;
fy = sin(fy) / fy;
}
if(kz != 0)
{
fz = (M_PI * kz) / PMGRID;
fz = sin(fz) / fz;
}
ff = 1 / (fx * fy * fz);
smth *= ff * ff * ff * ff;
/* end deconvolution */
ip = PMGRID * (PMGRID / 2 + 1) * (y - slabstart_y) + (PMGRID / 2 + 1) * x + z;
fft_of_rhogrid[ip].re *= smth;
fft_of_rhogrid[ip].im *= smth;
}
}
if(slabstart_y == 0)
fft_of_rhogrid[0].re = fft_of_rhogrid[0].im = 0.0;
/* Do the FFT to get the potential */
rfftwnd_mpi(fft_inverse_plan, 1, rhogrid, workspace, FFTW_TRANSPOSED_ORDER);
/* Now rhogrid holds the potential */
/* construct the potential for the local patch */
dimx = meshmax[0] - meshmin[0] + 6;
dimy = meshmax[1] - meshmin[1] + 6;
dimz = meshmax[2] - meshmin[2] + 6;
for(level = 0; level < (1 << PTask); level++) /* note: for level=0, target is the same task */
{
sendTask = ThisTask;
recvTask = ThisTask ^ level;
if(recvTask < NTask)
{
/* check how much we have to send */
sendmin = 2 * PMGRID;
sendmax = -PMGRID;
for(slab_x = meshmin_list[3 * recvTask] - 2; slab_x < meshmax_list[3 * recvTask] + 4; slab_x++)
if(slab_to_task[(slab_x + PMGRID) % PMGRID] == sendTask)
{
if(slab_x < sendmin)
sendmin = slab_x;
if(slab_x > sendmax)
sendmax = slab_x;
}
if(sendmax == -PMGRID)
sendmin = sendmax + 1;
/* check how much we have to receive */
recvmin = 2 * PMGRID;
recvmax = -PMGRID;
for(slab_x = meshmin[0] - 2; slab_x < meshmax[0] + 4; slab_x++)
if(slab_to_task[(slab_x + PMGRID) % PMGRID] == recvTask)
{
if(slab_x < recvmin)
recvmin = slab_x;
if(slab_x > recvmax)
recvmax = slab_x;
}
if(recvmax == -PMGRID)
recvmin = recvmax + 1;
if((recvmax - recvmin) >= 0 || (sendmax - sendmin) >= 0) /* ok, we have a contribution to the slab */
{
recv_dimx = meshmax_list[3 * recvTask + 0] - meshmin_list[3 * recvTask + 0] + 6;
recv_dimy = meshmax_list[3 * recvTask + 1] - meshmin_list[3 * recvTask + 1] + 6;
recv_dimz = meshmax_list[3 * recvTask + 2] - meshmin_list[3 * recvTask + 2] + 6;
ncont = 1;
cont_sendmin[0] = sendmin;
cont_sendmax[0] = sendmax;
cont_sendmin[1] = sendmax + 1;
cont_sendmax[1] = sendmax;
cont_recvmin[0] = recvmin;
cont_recvmax[0] = recvmax;
cont_recvmin[1] = recvmax + 1;
cont_recvmax[1] = recvmax;
for(slab_x = sendmin; slab_x <= sendmax; slab_x++)
{
if(slab_to_task[(slab_x + PMGRID) % PMGRID] != ThisTask)
{
/* non-contiguous */
cont_sendmax[0] = slab_x - 1;
while(slab_to_task[(slab_x + PMGRID) % PMGRID] != ThisTask)
slab_x++;
cont_sendmin[1] = slab_x;
ncont++;
}
}
for(slab_x = recvmin; slab_x <= recvmax; slab_x++)
{
if(slab_to_task[(slab_x + PMGRID) % PMGRID] != recvTask)
{
/* non-contiguous */
cont_recvmax[0] = slab_x - 1;
while(slab_to_task[(slab_x + PMGRID) % PMGRID] != recvTask)
slab_x++;
cont_recvmin[1] = slab_x;
if(ncont == 1)
ncont++;
}
}
for(rep = 0; rep < ncont; rep++)
{
sendmin = cont_sendmin[rep];
sendmax = cont_sendmax[rep];
recvmin = cont_recvmin[rep];
recvmax = cont_recvmax[rep];
/* prepare what we want to send */
if(sendmax - sendmin >= 0)
{
for(slab_x = sendmin; slab_x <= sendmax; slab_x++)
{
slab_xx = ((slab_x + PMGRID) % PMGRID) - first_slab_of_task[ThisTask];
for(slab_y = meshmin_list[3 * recvTask + 1] - 2;
slab_y < meshmax_list[3 * recvTask + 1] + 4; slab_y++)
{
slab_yy = (slab_y + PMGRID) % PMGRID;
for(slab_z = meshmin_list[3 * recvTask + 2] - 2;
slab_z <= meshmax_list[3 * recvTask + 2] + 4; slab_z++)
{
slab_zz = (slab_z + PMGRID) % PMGRID;
forcegrid[((slab_x - sendmin) * recv_dimy +
(slab_y - (meshmin_list[3 * recvTask + 1] - 2))) * recv_dimz +
slab_z - (meshmin_list[3 * recvTask + 2] - 2)] =
rhogrid[PMGRID * PMGRID2 * slab_xx + PMGRID2 * slab_yy + slab_zz];
}
}
}
}
if(level > 0)
{
MPI_Sendrecv(forcegrid,
(sendmax - sendmin + 1) * recv_dimy * recv_dimz * sizeof(fftw_real),
MPI_BYTE, recvTask, TAG_PERIODIC_B,
workspace + (recvmin - (meshmin[0] - 2)) * dimy * dimz,
(recvmax - recvmin + 1) * dimy * dimz * sizeof(fftw_real), MPI_BYTE,
recvTask, TAG_PERIODIC_B, MPI_COMM_WORLD, &status);
}
else
{
memcpy(workspace + (recvmin - (meshmin[0] - 2)) * dimy * dimz,
forcegrid, (recvmax - recvmin + 1) * dimy * dimz * sizeof(fftw_real));
}
}
}
}
}
dimx = meshmax[0] - meshmin[0] + 2;
dimy = meshmax[1] - meshmin[1] + 2;
dimz = meshmax[2] - meshmin[2] + 2;
recv_dimx = meshmax[0] - meshmin[0] + 6;
recv_dimy = meshmax[1] - meshmin[1] + 6;
recv_dimz = meshmax[2] - meshmin[2] + 6;
for(dim = 0; dim < 3; dim++) /* Calculate each component of the force. */
{
/* get the force component by finite differencing the potential */
/* note: "workspace" now contains the potential for the local patch, plus a suffiently large buffer region */
for(x = 0; x < meshmax[0] - meshmin[0] + 2; x++)
for(y = 0; y < meshmax[1] - meshmin[1] + 2; y++)
for(z = 0; z < meshmax[2] - meshmin[2] + 2; z++)
{
xrr = xll = xr = xl = x;
yrr = yll = yr = yl = y;
zrr = zll = zr = zl = z;
switch (dim)
{
case 0:
xr = x + 1;
xrr = x + 2;
xl = x - 1;
xll = x - 2;
break;
case 1:
yr = y + 1;
yl = y - 1;
yrr = y + 2;
yll = y - 2;
break;
case 2:
zr = z + 1;
zl = z - 1;
zrr = z + 2;
zll = z - 2;
break;
}
forcegrid[(x * dimy + y) * dimz + z]
=
fac * ((4.0 / 3) *
(workspace[((xl + 2) * recv_dimy + (yl + 2)) * recv_dimz + (zl + 2)]
- workspace[((xr + 2) * recv_dimy + (yr + 2)) * recv_dimz + (zr + 2)]) -
(1.0 / 6) *
(workspace[((xll + 2) * recv_dimy + (yll + 2)) * recv_dimz + (zll + 2)] -
workspace[((xrr + 2) * recv_dimy + (yrr + 2)) * recv_dimz + (zrr + 2)]));
}
/* read out the forces */
for(i = 0; i < NumPart; i++)
{
slab_x = to_slab_fac * P[i].Pos[0];
if(slab_x >= PMGRID)
slab_x = PMGRID - 1;
dx = to_slab_fac * P[i].Pos[0] - slab_x;
slab_x -= meshmin[0];
slab_xx = slab_x + 1;
slab_y = to_slab_fac * P[i].Pos[1];
if(slab_y >= PMGRID)
slab_y = PMGRID - 1;
dy = to_slab_fac * P[i].Pos[1] - slab_y;
slab_y -= meshmin[1];
slab_yy = slab_y + 1;
slab_z = to_slab_fac * P[i].Pos[2];
if(slab_z >= PMGRID)
slab_z = PMGRID - 1;
dz = to_slab_fac * P[i].Pos[2] - slab_z;
slab_z -= meshmin[2];
slab_zz = slab_z + 1;
acc_dim =
forcegrid[(slab_x * dimy + slab_y) * dimz + slab_z] * (1.0 - dx) * (1.0 - dy) * (1.0 - dz);
acc_dim += forcegrid[(slab_x * dimy + slab_yy) * dimz + slab_z] * (1.0 - dx) * dy * (1.0 - dz);
acc_dim += forcegrid[(slab_x * dimy + slab_y) * dimz + slab_zz] * (1.0 - dx) * (1.0 - dy) * dz;
acc_dim += forcegrid[(slab_x * dimy + slab_yy) * dimz + slab_zz] * (1.0 - dx) * dy * dz;
acc_dim += forcegrid[(slab_xx * dimy + slab_y) * dimz + slab_z] * (dx) * (1.0 - dy) * (1.0 - dz);
acc_dim += forcegrid[(slab_xx * dimy + slab_yy) * dimz + slab_z] * (dx) * dy * (1.0 - dz);
acc_dim += forcegrid[(slab_xx * dimy + slab_y) * dimz + slab_zz] * (dx) * (1.0 - dy) * dz;
acc_dim += forcegrid[(slab_xx * dimy + slab_yy) * dimz + slab_zz] * (dx) * dy * dz;
P[i].GravPM[dim] = acc_dim;
}
}
pm_init_periodic_free();
force_treeallocate(All.TreeAllocFactor * All.MaxPart, All.MaxPart);
All.NumForcesSinceLastDomainDecomp = 1 + All.TotNumPart * All.TreeDomainUpdateFrequency;
if(ThisTask == 0)
{
printf("done PM.\n");
fflush(stdout);
}
}
/*! Calculates the long-range potential using the PM method. The potential is
* Gaussian filtered with Asmth, given in mesh-cell units. We carry out a CIC
* charge assignment, and compute the potenial by Fourier transform
* methods. The CIC kernel is deconvolved.
*/
void pmpotential_periodic(void)
{
double k2, kx, ky, kz, smth;
double dx, dy, dz;
double fx, fy, fz, ff;
double asmth2, fac;
int i, j, slab, level, sendTask, recvTask;
int x, y, z, ip;
int slab_x, slab_y, slab_z;
int slab_xx, slab_yy, slab_zz;
int meshmin[3], meshmax[3], sendmin, sendmax, recvmin, recvmax;
int rep, ncont, cont_sendmin[2], cont_sendmax[2], cont_recvmin[2], cont_recvmax[2];
int dimx, dimy, dimz, recv_dimx, recv_dimy, recv_dimz;
MPI_Status status;
if(ThisTask == 0)
{
printf("Starting periodic PM calculation.\n");
fflush(stdout);
}
asmth2 = (2 * M_PI) * All.Asmth[0] / All.BoxSize;
asmth2 *= asmth2;
fac = All.G / (M_PI * All.BoxSize); /* to get potential */
force_treefree();
/* first, establish the extension of the local patch in the PMGRID */
for(j = 0; j < 3; j++)
{
meshmin[j] = PMGRID;
meshmax[j] = 0;
}
for(i = 0; i < NumPart; i++)
{
for(j = 0; j < 3; j++)
{
slab = to_slab_fac * P[i].Pos[j];
if(slab >= PMGRID)
slab = PMGRID - 1;
if(slab < meshmin[j])
meshmin[j] = slab;
if(slab > meshmax[j])
meshmax[j] = slab;
}
}
MPI_Allgather(meshmin, 3, MPI_INT, meshmin_list, 3, MPI_INT, MPI_COMM_WORLD);
MPI_Allgather(meshmax, 3, MPI_INT, meshmax_list, 3, MPI_INT, MPI_COMM_WORLD);
dimx = meshmax[0] - meshmin[0] + 2;
dimy = meshmax[1] - meshmin[1] + 2;
dimz = meshmax[2] - meshmin[2] + 2;
pm_init_periodic_allocate((dimx + 4) * (dimy + 4) * (dimz + 4));
for(i = 0; i < dimx * dimy * dimz; i++)
workspace[i] = 0;
for(i = 0; i < NumPart; i++)
{
slab_x = to_slab_fac * P[i].Pos[0];
if(slab_x >= PMGRID)
slab_x = PMGRID - 1;
dx = to_slab_fac * P[i].Pos[0] - slab_x;
slab_x -= meshmin[0];
slab_xx = slab_x + 1;
slab_y = to_slab_fac * P[i].Pos[1];
if(slab_y >= PMGRID)
slab_y = PMGRID - 1;
dy = to_slab_fac * P[i].Pos[1] - slab_y;
slab_y -= meshmin[1];
slab_yy = slab_y + 1;
slab_z = to_slab_fac * P[i].Pos[2];
if(slab_z >= PMGRID)
slab_z = PMGRID - 1;
dz = to_slab_fac * P[i].Pos[2] - slab_z;
slab_z -= meshmin[2];
slab_zz = slab_z + 1;
workspace[(slab_x * dimy + slab_y) * dimz + slab_z] += P[i].Mass * (1.0 - dx) * (1.0 - dy) * (1.0 - dz);
workspace[(slab_x * dimy + slab_yy) * dimz + slab_z] += P[i].Mass * (1.0 - dx) * dy * (1.0 - dz);
workspace[(slab_x * dimy + slab_y) * dimz + slab_zz] += P[i].Mass * (1.0 - dx) * (1.0 - dy) * dz;
workspace[(slab_x * dimy + slab_yy) * dimz + slab_zz] += P[i].Mass * (1.0 - dx) * dy * dz;
workspace[(slab_xx * dimy + slab_y) * dimz + slab_z] += P[i].Mass * (dx) * (1.0 - dy) * (1.0 - dz);
workspace[(slab_xx * dimy + slab_yy) * dimz + slab_z] += P[i].Mass * (dx) * dy * (1.0 - dz);
workspace[(slab_xx * dimy + slab_y) * dimz + slab_zz] += P[i].Mass * (dx) * (1.0 - dy) * dz;
workspace[(slab_xx * dimy + slab_yy) * dimz + slab_zz] += P[i].Mass * (dx) * dy * dz;
}
for(i = 0; i < fftsize; i++) /* clear local density field */
rhogrid[i] = 0;
for(level = 0; level < (1 << PTask); level++) /* note: for level=0, target is the same task */
{
sendTask = ThisTask;
recvTask = ThisTask ^ level;
if(recvTask < NTask)
{
/* check how much we have to send */
sendmin = 2 * PMGRID;
sendmax = -1;
for(slab_x = meshmin[0]; slab_x < meshmax[0] + 2; slab_x++)
if(slab_to_task[slab_x % PMGRID] == recvTask)
{
if(slab_x < sendmin)
sendmin = slab_x;
if(slab_x > sendmax)
sendmax = slab_x;
}
if(sendmax == -1)
sendmin = 0;
/* check how much we have to receive */
recvmin = 2 * PMGRID;
recvmax = -1;
for(slab_x = meshmin_list[3 * recvTask]; slab_x < meshmax_list[3 * recvTask] + 2; slab_x++)
if(slab_to_task[slab_x % PMGRID] == sendTask)
{
if(slab_x < recvmin)
recvmin = slab_x;
if(slab_x > recvmax)
recvmax = slab_x;
}
if(recvmax == -1)
recvmin = 0;
if((recvmax - recvmin) >= 0 || (sendmax - sendmin) >= 0) /* ok, we have a contribution to the slab */
{
recv_dimx = meshmax_list[3 * recvTask + 0] - meshmin_list[3 * recvTask + 0] + 2;
recv_dimy = meshmax_list[3 * recvTask + 1] - meshmin_list[3 * recvTask + 1] + 2;
recv_dimz = meshmax_list[3 * recvTask + 2] - meshmin_list[3 * recvTask + 2] + 2;
if(level > 0)
{
MPI_Sendrecv(workspace + (sendmin - meshmin[0]) * dimy * dimz,
(sendmax - sendmin + 1) * dimy * dimz * sizeof(fftw_real), MPI_BYTE, recvTask,
TAG_PERIODIC_C, forcegrid,
(recvmax - recvmin + 1) * recv_dimy * recv_dimz * sizeof(fftw_real), MPI_BYTE,
recvTask, TAG_PERIODIC_C, MPI_COMM_WORLD, &status);
}
else
{
memcpy(forcegrid, workspace + (sendmin - meshmin[0]) * dimy * dimz,
(sendmax - sendmin + 1) * dimy * dimz * sizeof(fftw_real));
}
for(slab_x = recvmin; slab_x <= recvmax; slab_x++)
{
slab_xx = (slab_x % PMGRID) - first_slab_of_task[ThisTask];
if(slab_xx >= 0 && slab_xx < slabs_per_task[ThisTask])
{
for(slab_y = meshmin_list[3 * recvTask + 1];
slab_y <= meshmax_list[3 * recvTask + 1] + 1; slab_y++)
{
slab_yy = slab_y;
if(slab_yy >= PMGRID)
slab_yy -= PMGRID;
for(slab_z = meshmin_list[3 * recvTask + 2];
slab_z <= meshmax_list[3 * recvTask + 2] + 1; slab_z++)
{
slab_zz = slab_z;
if(slab_zz >= PMGRID)
slab_zz -= PMGRID;
rhogrid[PMGRID * PMGRID2 * slab_xx + PMGRID2 * slab_yy + slab_zz] +=
forcegrid[((slab_x - recvmin) * recv_dimy +
(slab_y - meshmin_list[3 * recvTask + 1])) * recv_dimz +
(slab_z - meshmin_list[3 * recvTask + 2])];
}
}
}
}
}
}
}
/* Do the FFT of the density field */
rfftwnd_mpi(fft_forward_plan, 1, rhogrid, workspace, FFTW_TRANSPOSED_ORDER);
/* multiply with Green's function for the potential */
for(y = slabstart_y; y < slabstart_y + nslab_y; y++)
for(x = 0; x < PMGRID; x++)
for(z = 0; z < PMGRID / 2 + 1; z++)
{
if(x > PMGRID / 2)
kx = x - PMGRID;
else
kx = x;
if(y > PMGRID / 2)
ky = y - PMGRID;
else
ky = y;
if(z > PMGRID / 2)
kz = z - PMGRID;
else
kz = z;
k2 = kx * kx + ky * ky + kz * kz;
if(k2 > 0)
{
smth = -exp(-k2 * asmth2) / k2 * fac;
/* do deconvolution */
fx = fy = fz = 1;
if(kx != 0)
{
fx = (M_PI * kx) / PMGRID;
fx = sin(fx) / fx;
}
if(ky != 0)
{
fy = (M_PI * ky) / PMGRID;
fy = sin(fy) / fy;
}
if(kz != 0)
{
fz = (M_PI * kz) / PMGRID;
fz = sin(fz) / fz;
}
ff = 1 / (fx * fy * fz);
smth *= ff * ff * ff * ff;
/* end deconvolution */
ip = PMGRID * (PMGRID / 2 + 1) * (y - slabstart_y) + (PMGRID / 2 + 1) * x + z;
fft_of_rhogrid[ip].re *= smth;
fft_of_rhogrid[ip].im *= smth;
}
}
if(slabstart_y == 0)
fft_of_rhogrid[0].re = fft_of_rhogrid[0].im = 0.0;
/* Do the FFT to get the potential */
rfftwnd_mpi(fft_inverse_plan, 1, rhogrid, workspace, FFTW_TRANSPOSED_ORDER);
/* note: "rhogrid" now contains the potential */
dimx = meshmax[0] - meshmin[0] + 6;
dimy = meshmax[1] - meshmin[1] + 6;
dimz = meshmax[2] - meshmin[2] + 6;
for(level = 0; level < (1 << PTask); level++) /* note: for level=0, target is the same task */
{
sendTask = ThisTask;
recvTask = ThisTask ^ level;
if(recvTask < NTask)
{
/* check how much we have to send */
sendmin = 2 * PMGRID;
sendmax = -PMGRID;
for(slab_x = meshmin_list[3 * recvTask] - 2; slab_x < meshmax_list[3 * recvTask] + 4; slab_x++)
if(slab_to_task[(slab_x + PMGRID) % PMGRID] == sendTask)
{
if(slab_x < sendmin)
sendmin = slab_x;
if(slab_x > sendmax)
sendmax = slab_x;
}
if(sendmax == -PMGRID)
sendmin = sendmax + 1;
/* check how much we have to receive */
recvmin = 2 * PMGRID;
recvmax = -PMGRID;
for(slab_x = meshmin[0] - 2; slab_x < meshmax[0] + 4; slab_x++)
if(slab_to_task[(slab_x + PMGRID) % PMGRID] == recvTask)
{
if(slab_x < recvmin)
recvmin = slab_x;
if(slab_x > recvmax)
recvmax = slab_x;
}
if(recvmax == -PMGRID)
recvmin = recvmax + 1;
if((recvmax - recvmin) >= 0 || (sendmax - sendmin) >= 0) /* ok, we have a contribution to the slab */
{
recv_dimx = meshmax_list[3 * recvTask + 0] - meshmin_list[3 * recvTask + 0] + 6;
recv_dimy = meshmax_list[3 * recvTask + 1] - meshmin_list[3 * recvTask + 1] + 6;
recv_dimz = meshmax_list[3 * recvTask + 2] - meshmin_list[3 * recvTask + 2] + 6;
ncont = 1;
cont_sendmin[0] = sendmin;
cont_sendmax[0] = sendmax;
cont_sendmin[1] = sendmax + 1;
cont_sendmax[1] = sendmax;
cont_recvmin[0] = recvmin;
cont_recvmax[0] = recvmax;
cont_recvmin[1] = recvmax + 1;
cont_recvmax[1] = recvmax;
for(slab_x = sendmin; slab_x <= sendmax; slab_x++)
{
if(slab_to_task[(slab_x + PMGRID) % PMGRID] != ThisTask)
{
/* non-contiguous */
cont_sendmax[0] = slab_x - 1;
while(slab_to_task[(slab_x + PMGRID) % PMGRID] != ThisTask)
slab_x++;
cont_sendmin[1] = slab_x;
ncont++;
}
}
for(slab_x = recvmin; slab_x <= recvmax; slab_x++)
{
if(slab_to_task[(slab_x + PMGRID) % PMGRID] != recvTask)
{
/* non-contiguous */
cont_recvmax[0] = slab_x - 1;
while(slab_to_task[(slab_x + PMGRID) % PMGRID] != recvTask)
slab_x++;
cont_recvmin[1] = slab_x;
if(ncont == 1)
ncont++;
}
}
for(rep = 0; rep < ncont; rep++)
{
sendmin = cont_sendmin[rep];
sendmax = cont_sendmax[rep];
recvmin = cont_recvmin[rep];
recvmax = cont_recvmax[rep];
/* prepare what we want to send */
if(sendmax - sendmin >= 0)
{
for(slab_x = sendmin; slab_x <= sendmax; slab_x++)
{
slab_xx = ((slab_x + PMGRID) % PMGRID) - first_slab_of_task[ThisTask];
for(slab_y = meshmin_list[3 * recvTask + 1] - 2;
slab_y < meshmax_list[3 * recvTask + 1] + 4; slab_y++)
{
slab_yy = (slab_y + PMGRID) % PMGRID;
for(slab_z = meshmin_list[3 * recvTask + 2] - 2;
slab_z <= meshmax_list[3 * recvTask + 2] + 4; slab_z++)
{
slab_zz = (slab_z + PMGRID) % PMGRID;
forcegrid[((slab_x - sendmin) * recv_dimy +
(slab_y - (meshmin_list[3 * recvTask + 1] - 2))) * recv_dimz +
slab_z - (meshmin_list[3 * recvTask + 2] - 2)] =
rhogrid[PMGRID * PMGRID2 * slab_xx + PMGRID2 * slab_yy + slab_zz];
}
}
}
}
if(level > 0)
{
MPI_Sendrecv(forcegrid,
(sendmax - sendmin + 1) * recv_dimy * recv_dimz * sizeof(fftw_real),
MPI_BYTE, recvTask, TAG_PERIODIC_D,
workspace + (recvmin - (meshmin[0] - 2)) * dimy * dimz,
(recvmax - recvmin + 1) * dimy * dimz * sizeof(fftw_real), MPI_BYTE,
recvTask, TAG_PERIODIC_D, MPI_COMM_WORLD, &status);
}
else
{
memcpy(workspace + (recvmin - (meshmin[0] - 2)) * dimy * dimz,
forcegrid, (recvmax - recvmin + 1) * dimy * dimz * sizeof(fftw_real));
}
}
}
}
}
dimx = meshmax[0] - meshmin[0] + 2;
dimy = meshmax[1] - meshmin[1] + 2;
dimz = meshmax[2] - meshmin[2] + 2;
recv_dimx = meshmax[0] - meshmin[0] + 6;
recv_dimy = meshmax[1] - meshmin[1] + 6;
recv_dimz = meshmax[2] - meshmin[2] + 6;
for(x = 0; x < meshmax[0] - meshmin[0] + 2; x++)
for(y = 0; y < meshmax[1] - meshmin[1] + 2; y++)
for(z = 0; z < meshmax[2] - meshmin[2] + 2; z++)
{
forcegrid[(x * dimy + y) * dimz + z] =
workspace[((x + 2) * recv_dimy + (y + 2)) * recv_dimz + (z + 2)];
}
/* read out the potential */
for(i = 0; i < NumPart; i++)
{
slab_x = to_slab_fac * P[i].Pos[0];
if(slab_x >= PMGRID)
slab_x = PMGRID - 1;
dx = to_slab_fac * P[i].Pos[0] - slab_x;
slab_x -= meshmin[0];
slab_xx = slab_x + 1;
slab_y = to_slab_fac * P[i].Pos[1];
if(slab_y >= PMGRID)
slab_y = PMGRID - 1;
dy = to_slab_fac * P[i].Pos[1] - slab_y;
slab_y -= meshmin[1];
slab_yy = slab_y + 1;
slab_z = to_slab_fac * P[i].Pos[2];
if(slab_z >= PMGRID)
slab_z = PMGRID - 1;
dz = to_slab_fac * P[i].Pos[2] - slab_z;
slab_z -= meshmin[2];
slab_zz = slab_z + 1;
P[i].Potential +=
forcegrid[(slab_x * dimy + slab_y) * dimz + slab_z] * (1.0 - dx) * (1.0 - dy) * (1.0 - dz);
P[i].Potential += forcegrid[(slab_x * dimy + slab_yy) * dimz + slab_z] * (1.0 - dx) * dy * (1.0 - dz);
P[i].Potential += forcegrid[(slab_x * dimy + slab_y) * dimz + slab_zz] * (1.0 - dx) * (1.0 - dy) * dz;
P[i].Potential += forcegrid[(slab_x * dimy + slab_yy) * dimz + slab_zz] * (1.0 - dx) * dy * dz;
P[i].Potential += forcegrid[(slab_xx * dimy + slab_y) * dimz + slab_z] * (dx) * (1.0 - dy) * (1.0 - dz);
P[i].Potential += forcegrid[(slab_xx * dimy + slab_yy) * dimz + slab_z] * (dx) * dy * (1.0 - dz);
P[i].Potential += forcegrid[(slab_xx * dimy + slab_y) * dimz + slab_zz] * (dx) * (1.0 - dy) * dz;
P[i].Potential += forcegrid[(slab_xx * dimy + slab_yy) * dimz + slab_zz] * (dx) * dy * dz;
}
pm_init_periodic_free();
force_treeallocate(All.TreeAllocFactor * All.MaxPart, All.MaxPart);
All.NumForcesSinceLastDomainDecomp = 1 + All.TotNumPart * All.TreeDomainUpdateFrequency;
if(ThisTask == 0)
{
printf("done PM-Potential.\n");
fflush(stdout);
}
}
#endif
#endif

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