#pragma OPENCL EXTENSION cl_khr_global_int32_base_atomics : enable #ifdef SUPPORTS_64_BIT_ATOMICS #pragma OPENCL EXTENSION cl_khr_int64_base_atomics : enable #endif #define TILE_SIZE 32 /** * Compute a value based on pair interactions. */ __kernel void computeN2Value(__global const real4* restrict posq, __local real4* restrict local_posq, __global const unsigned int* restrict exclusions, __global const unsigned int* restrict exclusionIndices, __global const unsigned int* restrict exclusionRowIndices, #ifdef SUPPORTS_64_BIT_ATOMICS __global long* restrict global_value, #else __global real* restrict global_value, #endif __local real* restrict local_value, __local real* restrict tempBuffer, #ifdef USE_CUTOFF __global const ushort2* restrict tiles, __global const unsigned int* restrict interactionCount, real4 periodicBoxSize, real4 invPeriodicBoxSize, unsigned int maxTiles, __global const unsigned int* restrict interactionFlags #else unsigned int numTiles #endif PARAMETER_ARGUMENTS) { unsigned int totalWarps = get_global_size(0)/TILE_SIZE; unsigned int warp = get_global_id(0)/TILE_SIZE; #ifdef USE_CUTOFF unsigned int numTiles = interactionCount[0]; unsigned int pos = warp*(numTiles > maxTiles ? NUM_BLOCKS*(NUM_BLOCKS+1)/2 : numTiles)/totalWarps; unsigned int end = (warp+1)*(numTiles > maxTiles ? NUM_BLOCKS*(NUM_BLOCKS+1)/2 : numTiles)/totalWarps; #else unsigned int pos = warp*numTiles/totalWarps; unsigned int end = (warp+1)*numTiles/totalWarps; #endif real energy = 0; unsigned int lasty = 0xFFFFFFFF; __local unsigned int exclusionRange[2*WARPS_PER_GROUP]; __local int exclusionIndex[WARPS_PER_GROUP]; __local int2* reservedBlocks = (__local int2*) exclusionRange; do { // Extract the coordinates of this tile const unsigned int tgx = get_local_id(0) & (TILE_SIZE-1); const unsigned int tbx = get_local_id(0) - tgx; const unsigned int localGroupIndex = get_local_id(0)/TILE_SIZE; unsigned int x, y; real value = 0; if (pos < end) { #ifdef USE_CUTOFF if (numTiles <= maxTiles) { ushort2 tileIndices = tiles[pos]; x = tileIndices.x; y = tileIndices.y; } else #endif { y = (unsigned int) floor(NUM_BLOCKS+0.5f-SQRT((NUM_BLOCKS+0.5f)*(NUM_BLOCKS+0.5f)-2*pos)); x = (pos-y*NUM_BLOCKS+y*(y+1)/2); if (x < y || x >= NUM_BLOCKS) { // Occasionally happens due to roundoff error. y += (x < y ? -1 : 1); x = (pos-y*NUM_BLOCKS+y*(y+1)/2); } } unsigned int atom1 = x*TILE_SIZE + tgx; real4 posq1 = posq[atom1]; LOAD_ATOM1_PARAMETERS // Locate the exclusion data for this tile. #ifdef USE_EXCLUSIONS if (tgx < 2) exclusionRange[2*localGroupIndex+tgx] = exclusionRowIndices[x+tgx]; if (tgx == 0) exclusionIndex[localGroupIndex] = -1; for (unsigned int i = exclusionRange[2*localGroupIndex]+tgx; i < exclusionRange[2*localGroupIndex+1]; i += TILE_SIZE) if (exclusionIndices[i] == y) exclusionIndex[localGroupIndex] = i*TILE_SIZE; bool hasExclusions = (exclusionIndex[localGroupIndex] > -1); #else bool hasExclusions = false; #endif if (pos >= end) ; // This warp is done. else if (x == y) { // This tile is on the diagonal. const unsigned int localAtomIndex = get_local_id(0); local_posq[localAtomIndex] = posq1; LOAD_LOCAL_PARAMETERS_FROM_1 #ifdef USE_EXCLUSIONS unsigned int excl = exclusions[exclusionIndex[localGroupIndex]+tgx]; #endif for (unsigned int j = 0; j < TILE_SIZE; j++) { #ifdef USE_EXCLUSIONS bool isExcluded = !(excl & 0x1); #endif int atom2 = tbx+j; real4 posq2 = local_posq[atom2]; real4 delta = (real4) (posq2.xyz - posq1.xyz, 0); #ifdef USE_PERIODIC delta.x -= floor(delta.x*invPeriodicBoxSize.x+0.5f)*periodicBoxSize.x; delta.y -= floor(delta.y*invPeriodicBoxSize.y+0.5f)*periodicBoxSize.y; delta.z -= floor(delta.z*invPeriodicBoxSize.z+0.5f)*periodicBoxSize.z; #endif real r2 = delta.x*delta.x + delta.y*delta.y + delta.z*delta.z; #ifdef USE_CUTOFF if (r2 < CUTOFF_SQUARED) { #endif real invR = RSQRT(r2); real r = RECIP(invR); LOAD_ATOM2_PARAMETERS atom2 = y*TILE_SIZE+j; real tempValue1 = 0; real tempValue2 = 0; #ifdef USE_EXCLUSIONS if (!isExcluded && atom1 < NUM_ATOMS && atom2 < NUM_ATOMS && atom1 != atom2) { #else if (atom1 < NUM_ATOMS && atom2 < NUM_ATOMS && atom1 != atom2) { #endif COMPUTE_VALUE } value += tempValue1; #ifdef USE_CUTOFF } #endif #ifdef USE_EXCLUSIONS excl >>= 1; #endif } } else { // This is an off-diagonal tile. if (lasty != y) { unsigned int j = y*TILE_SIZE + tgx; local_posq[get_local_id(0)] = posq[j]; const unsigned int localAtomIndex = get_local_id(0); LOAD_LOCAL_PARAMETERS_FROM_GLOBAL } local_value[get_local_id(0)] = 0; #ifdef USE_CUTOFF unsigned int flags = (numTiles <= maxTiles ? interactionFlags[pos] : 0xFFFFFFFF); if (!hasExclusions && flags != 0xFFFFFFFF) { if (flags == 0) { // No interactions in this tile. } else { // Compute only a subset of the interactions in this tile. for (unsigned int j = 0; j < TILE_SIZE; j++) { if ((flags&(1<> tgx) | (excl << (TILE_SIZE - tgx)); #endif unsigned int tj = tgx; for (unsigned int j = 0; j < TILE_SIZE; j++) { #ifdef USE_EXCLUSIONS bool isExcluded = !(excl & 0x1); #endif int atom2 = tbx+tj; real4 posq2 = local_posq[atom2]; real4 delta = (real4) (posq2.xyz - posq1.xyz, 0); #ifdef USE_PERIODIC delta.x -= floor(delta.x*invPeriodicBoxSize.x+0.5f)*periodicBoxSize.x; delta.y -= floor(delta.y*invPeriodicBoxSize.y+0.5f)*periodicBoxSize.y; delta.z -= floor(delta.z*invPeriodicBoxSize.z+0.5f)*periodicBoxSize.z; #endif real r2 = delta.x*delta.x + delta.y*delta.y + delta.z*delta.z; #ifdef USE_CUTOFF if (r2 < CUTOFF_SQUARED) { #endif real invR = RSQRT(r2); real r = RECIP(invR); LOAD_ATOM2_PARAMETERS atom2 = y*TILE_SIZE+tj; real tempValue1 = 0; real tempValue2 = 0; #ifdef USE_EXCLUSIONS if (!isExcluded && atom1 < NUM_ATOMS && atom2 < NUM_ATOMS) { #else if (atom1 < NUM_ATOMS && atom2 < NUM_ATOMS) { #endif COMPUTE_VALUE } value += tempValue1; local_value[tbx+tj] += tempValue2; #ifdef USE_CUTOFF } #endif #ifdef USE_EXCLUSIONS excl >>= 1; #endif tj = (tj + 1) & (TILE_SIZE - 1); } } } } // Write results. We need to coordinate between warps to make sure no two of them // ever try to write to the same piece of memory at the same time. #ifdef SUPPORTS_64_BIT_ATOMICS if (pos < end) { const unsigned int offset = x*TILE_SIZE + tgx; atom_add(&global_value[offset], (long) (value*0xFFFFFFFF)); } if (pos < end && x != y) { const unsigned int offset = y*TILE_SIZE + tgx; atom_add(&global_value[offset], (long) (local_value[get_local_id(0)]*0xFFFFFFFF)); } #else int writeX = (pos < end ? x : -1); int writeY = (pos < end && x != y ? y : -1); if (tgx == 0) reservedBlocks[localGroupIndex] = (int2)(writeX, writeY); bool done = false; int doneIndex = 0; int checkIndex = 0; while (true) { // See if any warp still needs to write its data. bool allDone = true; barrier(CLK_LOCAL_MEM_FENCE); while (doneIndex < WARPS_PER_GROUP && allDone) { if (reservedBlocks[doneIndex].x != -1) allDone = false; else doneIndex++; } if (allDone) break; if (!done) { // See whether this warp can write its data. This requires that no previous warp // is trying to write to the same block of the buffer. bool canWrite = (writeX != -1); while (checkIndex < localGroupIndex && canWrite) { if ((reservedBlocks[checkIndex].x == x || reservedBlocks[checkIndex].y == x) || (writeY != -1 && (reservedBlocks[checkIndex].x == y || reservedBlocks[checkIndex].y == y))) canWrite = false; else checkIndex++; } if (canWrite) { // Write the data to global memory, then mark this warp as done. if (writeX > -1) { const unsigned int offset = x*TILE_SIZE + tgx + get_group_id(0)*PADDED_NUM_ATOMS; global_value[offset] += value; } if (writeY > -1) { const unsigned int offset = y*TILE_SIZE + tgx + get_group_id(0)*PADDED_NUM_ATOMS; global_value[offset] += local_value[get_local_id(0)]; } done = true; if (tgx == 0) reservedBlocks[localGroupIndex] = (int2)(-1, -1); } } } #endif lasty = y; pos++; } while (pos < end); }