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Evghenii
2014-01-30 20:01:34 +01:00
parent adef91d82d
commit eb3277587a
4 changed files with 104 additions and 121 deletions
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125
examples_ptx/nbody/nbody.ispc
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@@ -26,6 +26,8 @@ void closeNbody()
delete gpotList;
}
uniform int nn = programCount;
task
void computeForces(
@@ -39,45 +41,9 @@ void computeForces(
const uniform int blockDim = (nbodies + taskCount - 1)/taskCount;
const uniform int blockBeg = blockIdx * blockDim;
const uniform int blockEnd = min(blockBeg + blockDim, nbodies);
uniform real shmem[4*programCount];
#if 0
uniform real gpotLoc = 0;
for (uniform int i = blockBeg; i < blockEnd; i++)
{
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;
foreach (j = 0 ... nbodies)
{
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 = r2 > 0.0d ? rsqrt((float)r2) : 0;
const real mrinv = -jmass * rinv;
const real mrinv3 = mrinv * rinv*rinv;
iaccx += mrinv3 * dx;
iaccy += mrinv3 * dy;
iaccz += mrinv3 * dz;
igpot += mrinv;
}
accx[i] = reduce_add(iaccx);
accy[i] = reduce_add(iaccy);
accz[i] = reduce_add(iaccz);
gpotLoc += reduce_add(igpot);
}
gpotList[taskIndex] = gpotLoc;
#else
real gpotLoc = 0;
//real gpotLoc = 0;
foreach (i = blockBeg ... blockEnd)
{
const real iposx = posx[i];
@@ -87,35 +53,60 @@ void computeForces(
real iaccy = 0;
real iaccz = 0;
real igpot = 0;
for (uniform int j = 0; j < nbodies; j += 1)
#if 0
for (uniform int j = 0; j < nbodies; j++)
{
#define STEP(jk) {\
const real jposx = posx[j+jk]; \
const real jposy = posy[j+jk]; \
const real jposz = posz[j+jk]; \
const real jmass = mass[j+jk]; \
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 = r2 > 0.0d ? rsqrt((float)r2) : 0; \
const real mrinv = -jmass * rinv; \
const real mrinv3 = mrinv * rinv*rinv; \
\
iaccx += mrinv3 * dx; \
iaccy += mrinv3 * dy; \
iaccz += mrinv3 * dz; \
igpot += mrinv; \
}
STEP(0)
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 = r2 > 0.0d ? rsqrt((float)r2) : 0;
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)
{
shmem[0*programCount + programIndex] = posx[j+programIndex];
shmem[1*programCount + programIndex] = posy[j+programIndex];
shmem[2*programCount + programIndex] = posz[j+programIndex];
shmem[3*programCount + programIndex] = mass[j+programIndex];
for (uniform int jb = 0; jb < programCount; jb++)
{
const real jposx = shmem[0*programCount + jb];
const real jposy = shmem[1*programCount + jb];
const real jposz = shmem[2*programCount + jb];
const real jmass = shmem[3*programCount + jb];
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 = r2; // > 0.0d ? rsqrt((float)r2) : 0;
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;
gpotLoc += igpot;
// gpotLoc += igpot;
}
gpotList[taskIndex] = reduce_add(gpotLoc);
#endif
// gpotList[taskIndex] = reduce_add(gpotLoc);
}
task
@@ -179,20 +170,21 @@ void nbodyIntegrate(
{
uniform int nTasks = num_cores()*4;
#ifdef __NVPTX__
nTasks = nbodies/(4*programCount);
nTasks = (nbodies + 4*programCount - 1)/(4*programCount);
#endif
assert((nbodies % nTasks) == 0);
for (uniform int step = 0; step < nSteps; step++)
{
launch [nTasks] updatePositions(nbodies, posx, posy, posz, velx, vely, velz,dt);
sync;
// launch [nTasks] updatePositions(nbodies, posx, posy, posz, velx, vely, velz,dt);
// sync;
launch [nTasks] computeForces(nbodies, posx, posy, posz, mass);
sync;
launch [nTasks] updateVelocities(nbodies, posx, posy, posz, dt);
sync;
// launch [nTasks] updateVelocities(nbodies, posx, posy, posz, dt);
// sync;
}
#if 0
if (energies != NULL)
{
real gpotLoc = 0;
@@ -200,6 +192,7 @@ void nbodyIntegrate(
gpotLoc += gpotList[i];
energies[0] = reduce_add(gpotLoc);
}
#endif
}