Files
ispc/examples_ptx/nbody/nbody.cu
Evghenii 1a56fbc101 +1
2014-02-03 08:51:55 +01:00

262 lines
6.5 KiB
Plaintext

#include "realType.h"
#include "cuda_helpers.cuh"
#include <cassert>
#define uniform
__device__ static uniform real * uniform accx = NULL;
__device__ static uniform real * uniform accy;
__device__ static uniform real * uniform accz;
__device__ static uniform real * uniform gpotList;
__global__
void openNbody___export(const uniform int n)
{
assert(accx == NULL);
accx = uniform new uniform real[n];
accy = uniform new uniform real[n];
accz = uniform new uniform real[n];
gpotList = uniform new uniform real[n];
}
extern "C"
void openNbody(int n)
{
openNbody___export<<<1,1>>>(n);
}
__global__
void closeNbody___export()
{
assert(accx != NULL);
delete accx;
delete accy;
delete accz;
delete gpotList;
}
extern "C"
void closeNbody()
{
closeNbody___export<<<1,1>>>();
}
static inline __device__
real rsqrt_real(real r2)
{
#if 0
return r2> (real)0.0 ? (real)1.0/sqrt(r2) : 0;
#else
return r2> (real)0.0 ? rsqrt((float)r2) : 0;
#endif
}
__global__
void computeForces(
uniform int nbodies,
uniform real posx[],
uniform real posy[],
uniform real posz[],
uniform real mass[])
{
const uniform int blkIdx = taskIndex;
const uniform int blkDim = (nbodies + taskCount - 1)/taskCount;
const uniform int blkBeg = blkIdx * blkDim;
const uniform int blkEnd = min(blkBeg + blkDim, nbodies);
for (int i = programIndex + blkBeg; i < blkEnd; i += programCount)
if (i < blkEnd)
{
const real iposx = posx[i];
const real iposy = posy[i];
const real iposz = posz[i];
real iaccx = 0;
real iaccy = 0;
real iaccz = 0;
real igpot = 0;
#if 0
for (uniform int j = 0; j < nbodies; j++)
{
const real jposx = posx[j];
const real jposy = posy[j];
const real jposz = posz[j];
const real jmass = mass[j];
const real dx = jposx - iposx;
const real dy = jposy - iposy;
const real dz = jposz - iposz;
const real r2 = dx*dx + dy*dy + dz*dz;
const real rinv = rsqrt_real(r2);
const real mrinv = -jmass * rinv;
const real mrinv3 = mrinv * rinv*rinv;
iaccx += mrinv3 * dx;
iaccy += mrinv3 * dy;
iaccz += mrinv3 * dz;
igpot += mrinv;
}
#else
for (uniform int j = 0; j < nbodies; j += programCount)
{
#if 1
__shared__ real shdata[4][programCount*4];
real (* shmem)[programCount] = (real (*)[programCount])shdata[warpIdx];
shmem[0][programIndex] = posx[j+programIndex];
shmem[1][programIndex] = posy[j+programIndex];
shmem[2][programIndex] = posz[j+programIndex];
shmem[3][programIndex] = mass[j+programIndex];
#else
const real jPosx = posx[j+programIndex];
const real jPosy = posy[j+programIndex];
const real jPosz = posz[j+programIndex];
const real jMass = mass[j+programIndex];
#endif
#pragma unroll 1
for (int jb = 0; jb < programCount; jb++)
{
#if 1
const real jposx = shmem[0][jb];
const real jposy = shmem[1][jb];
const real jposz = shmem[2][jb];
const real jmass = shmem[3][jb];
#else
const real jposx = broadcast(jPosx, jb);
const real jposy = broadcast(jPosy, jb);
const real jposz = broadcast(jPosz, jb);
const real jmass = broadcast(jMass, jb);
#endif
const real dx = jposx - iposx;
const real dy = jposy - iposy;
const real dz = jposz - iposz;
const real r2 = dx*dx + dy*dy + dz*dz;
const real rinv = rsqrt_real(r2);
const real mrinv = -jmass * rinv;
const real mrinv3 = mrinv * rinv*rinv;
iaccx += mrinv3 * dx;
iaccy += mrinv3 * dy;
iaccz += mrinv3 * dz;
igpot += mrinv;
}
}
#endif
accx[i] = iaccx;
accy[i] = iaccy;
accz[i] = iaccz;
}
}
__global__
void updatePositions(
uniform int nbodies,
uniform real posx[],
uniform real posy[],
uniform real posz[],
uniform real velx[],
uniform real vely[],
uniform real velz[],
uniform real dt)
{
const uniform int blkIdx = taskIndex;
const uniform int blkDim = (nbodies + taskCount - 1)/taskCount;
const uniform int blkBeg = blkIdx * blkDim;
const uniform int blkEnd = min(blkBeg + blkDim, nbodies);
for (int i = programIndex + blkBeg; i < blkEnd; i += programCount)
if (i < blkEnd)
{
posx[i] += dt*velx[i];
posy[i] += dt*vely[i];
posz[i] += dt*velz[i];
}
}
__global__
void updateVelocities(
uniform int nbodies,
uniform real velx[],
uniform real vely[],
uniform real velz[],
uniform real dt)
{
const uniform int blkIdx = taskIndex;
const uniform int blkDim = (nbodies + taskCount - 1)/taskCount;
const uniform int blkBeg = blkIdx * blkDim;
const uniform int blkEnd = min(blkBeg + blkDim, nbodies);
for (int i = programIndex + blkBeg; i < blkEnd; i += programCount)
if (i < blkEnd)
{
velx[i] += dt*accx[i];
vely[i] += dt*accy[i];
velz[i] += dt*accz[i];
}
}
__global__
void nbodyIntegrate___export(
uniform int nSteps,
uniform int nbodies,
uniform real dt,
uniform real posx[],
uniform real posy[],
uniform real posz[],
uniform real mass[],
uniform real velx[],
uniform real vely[],
uniform real velz[],
uniform real energies[])
{
uniform int nTasks ;
nTasks = (nbodies+1*programCount - 1)/(1*programCount);
for (uniform int step = 0; step < nSteps; step++)
{
// launch (nTasks,1,1, updatePositions)(nbodies, posx, posy, posz, velx, vely, velz,dt);
// sync;
launch (nTasks,1,1, computeForces)(nbodies, posx, posy, posz, mass);
sync;
// launch (nTasks,1,1, updateVelocities)(nbodies, posx, posy, posz, dt);
//sync;
}
#if 0
if (energies != NULL)
{
real gpotLoc = 0;
foreach (i = 0 ... nTasks)
gpotLoc += gpotList[i];
energies[0] = reduce_add(gpotLoc);
}
#endif
}
extern "C"
void nbodyIntegrate(
uniform int nSteps,
uniform int nbodies,
uniform real dt,
uniform real posx[],
uniform real posy[],
uniform real posz[],
uniform real mass[],
uniform real velx[],
uniform real vely[],
uniform real velz[],
uniform real energies[])
{
cudaDeviceSetCacheConfig ( cudaFuncCachePreferEqual );
nbodyIntegrate___export<<<1,32>>>(
nSteps,
nbodies,
dt,
posx,
posy,
posz,
mass,
velx,
vely,
velz,
energies);
sync;
}