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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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94
examples_ptx/nbody/nbody.cu
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@@ -54,44 +54,6 @@ void computeForces(
const uniform int blkBeg = blkIdx * blkDim;
const uniform int blkEnd = min(blkBeg + blkDim, nbodies);
#if 0
uniform real gpotLoc = 0;
for (uniform int i = blkBeg; i < blkEnd; 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;
for (int i = programIndex + blkBeg; i < blkEnd; i += programCount)
if (i < blkEnd)
{
@@ -102,17 +64,18 @@ void computeForces(
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 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 > 0.0 ? rsqrt((float)r2) : 0;
const real rinv = r2; // > 0.0 ? rsqrt((float)r2) : 0;
const real mrinv = -jmass * rinv;
const real mrinv3 = mrinv * rinv*rinv;
iaccx += mrinv3 * dx;
@@ -120,13 +83,41 @@ void computeForces(
iaccz += mrinv3 * dz;
igpot += mrinv;
}
#else
for (uniform int j = 0; j < nbodies; j += programCount)
{
__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];
#pragma unroll 1
for (int jb = 0; jb < programCount; jb++)
{
const real jposx = shmem[0][jb];
const real jposy = shmem[1][jb];
const real jposz = shmem[2][jb];
const real jmass = shmem[3][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 ; //> 0.0 ? 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;
}
// gpotList[taskIndex] = reduce_add(gpotLoc);
#endif
}
__global__
@@ -191,17 +182,16 @@ void nbodyIntegrate___export(
uniform real energies[])
{
uniform int nTasks ;
nTasks = nbodies/(4*programCount);
assert((nbodies % nTasks) == 0);
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, 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;
// launch (nTasks,1,1, updateVelocities)(nbodies, posx, posy, posz, dt);
//sync;
}
#if 0