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lammps/lib/gpu/pppm_gpu_kernel.cu
2011-02-02 17:47:22 -05:00

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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing authors: Mike Brown (ORNL), brownw@ornl.gov
------------------------------------------------------------------------- */
#ifndef PPPM_GPU_KERNEL
#define PPPM_GPU_KERNEL
#define OFFSET 16384
#ifdef _DOUBLE_DOUBLE
#define numtyp double
#define numtyp2 double2
#define numtyp4 double4
#define acctyp double
#define acctyp4 double4
#endif
#ifdef _SINGLE_DOUBLE
#define numtyp float
#define numtyp2 float2
#define numtyp4 float4
#define acctyp double
#define acctyp4 double4
#endif
#ifndef numtyp
#define numtyp float
#define numtyp2 float2
#define numtyp4 float4
#define acctyp float
#define acctyp4 float4
#endif
#ifdef NV_KERNEL
#include "geryon/ucl_nv_kernel.h"
texture<float4> pos_tex;
texture<float> q_tex;
#ifdef _DOUBLE_DOUBLE
__inline double4 fetch_pos(const int& i, const double4 *pos)
{
return pos[i];
}
__inline double fetch_q(const int& i, const double *q)
{
return q[i];
}
#else
__inline float4 fetch_pos(const int& i, const float4 *pos)
{
return tex1Dfetch(pos_tex, i);
}
__inline float fetch_q(const int& i, const float *q)
{
return tex1Dfetch(q_tex, i);
}
#endif
#else
#pragma OPENCL EXTENSION cl_khr_fp64: enable
#pragma OPENCL EXTENSION cl_khr_local_int32_base_atomics : enable
#define GLOBAL_ID_X get_global_id(0)
#define THREAD_ID_X get_local_id(0)
#define BLOCK_ID_X get_group_id(0)
#define BLOCK_SIZE_X get_local_size(0)
#define __syncthreads() barrier(CLK_LOCAL_MEM_FENCE)
#define __inline inline
#define fetch_pos(i,y) x_[i]
#define fetch_q(i,y) q_[i]
#endif
__kernel void particle_map(__global numtyp4 *x_, const int nlocal,
__global int *counts, __global int *ans,
const numtyp boxlo_x, const numtyp boxlo_y,
const numtyp boxlo_z, const numtyp delxinv,
const numtyp delyinv, const numtyp delzinv,
const int npts_x, const int npts_y,
const int npts_z, const int _brick_stride,
const int max_atoms, __global int *error) {
// ii indexes the two interacting particles in gi
int ii=GLOBAL_ID_X;
int nx,ny,nz;
numtyp tx,ty,tz;
if (ii<nlocal) {
numtyp4 p=fetch_pos(ii,x_);
// Boxlo is adjusted to include ghost cells so that starting index is 0
tx=(p.x-boxlo_x)*delxinv;
nx=int(tx);
ty=(p.y-boxlo_y)*delyinv;
ny=int(ty);
tz=(p.z-boxlo_z)*delzinv;
nz=int(tz);
if (tx<0 || ty<0 || tz<0 || nx>=npts_x || ny>=npts_y || nz>=npts_z)
*error=1;
else {
int i=nz*npts_y*npts_x+ny*npts_x+nx;
int old=atom_add(counts+i, 1);
if (old==max_atoms)
*error=2;
else
ans[_brick_stride*old+i]=ii;
}
}
}
/*
__kernel void particle_map(__global numtyp4 *x_, __global numtyp *q_,
__global int *counts, __global int *atoms,
const numtyp boxlo_x, const numtyp boxlo_y,
const numtyp boxlo_z, const numtyp delxinv,
const numtyp delyinv, const numtyp delzinv,
const int npts_x, const int npts_y,
const int npts_z, const int _brick_stride,
const int max_atoms, __global int *error) {
// ii indexes the two interacting particles in gi
int xx=THREAD_ID_X;
int yy=THREAD_ID_Y;
int bx=BLOCK_ID_X;
int by=BLOCK_ID_Y;
int block_size=BLOCK_SIZE_X;
int max_y=BLOCK_ID_Y*block_size+block_size;
int max_x=BLOCK_ID_X*block_size+block_size;
__local numtyp4 p;
__local numtyp q,dx,dy,dz;
__local int brick_i,count,atom_i;
for (int z=-nlower; z<npts_z-order; z++)
for (int ny=max_y-block_size; ny<max_y; ny++) {
if (ny>npts_y)
break;
brick_i = z*npts_x*npts_y + ny*npts_x + max_x - block_size;
for (int nx=max_x-block_size; nx<max_x; nx++) {
if (nx>npts_x)
break;
count=counts[brick_i];
for (int i=0; i<count; i++) {
int atom_i=atoms[brick_i+i*_brick_stride];
p=fetch_pos(x_,atom_i);
q=fetch_q(q_,atom_i);
dx = nx+shiftone - (x[i][0]-boxlo[0])*delxinv;
dy = ny+shiftone - (x[i][1]-boxlo[1])*delyinv;
dz = nz+shiftone - (x[i][2]-boxlo[2])*delzinv;
brick_i++;
int nx=GLOBAL_ID_X+nlower;
int ny=GLOBAL_ID_Y+nlower;
int block_size=BLOCK_SIZE_X;
for (
// (nx,ny,nz) = global coords of grid pt to "lower left" of charge
// (dx,dy,dz) = distance to "lower left" grid pt
// (mx,my,mz) = global coords of moving stencil pt
double *q = atom->q;
double **x = atom->x;
int nlocal = atom->nlocal;
for (int i = 0; i < nlocal; i++) {
nx = part2grid[i][0];
ny = part2grid[i][1];
nz = part2grid[i][2];
compute_rho1d(dx,dy,dz);
z0 = delvolinv * q[i];
for (n = nlower; n <= nupper; n++) {
mz = n+nz; // z-index of point being updated
y0 = z0*rho1d[2][n];
for (m = nlower; m <= nupper; m++) {
my = m+ny;
x0 = y0*rho1d[1][m];
for (l = nlower; l <= nupper; l++) {
mx = l+nx;
density_brick[mz][my][mx] += x0*rho1d[0][l];
}
}
}
}
}
void PPPMGPU::compute_rho1d(double dx, double dy, double dz)
{
int k,l;
for (k = (1-order)/2; k <= order/2; k++) {
rho1d[0][k] = 0.0;
rho1d[1][k] = 0.0;
rho1d[2][k] = 0.0;
for (l = order-1; l >= 0; l--) {
rho1d[0][k] = rho_coeff[l][k] + rho1d[0][k]*dx;
rho1d[1][k] = rho_coeff[l][k] + rho1d[1][k]*dy;
rho1d[2][k] = rho_coeff[l][k] + rho1d[2][k]*dz;
}
}
}
*/
#endif