Fixed numeric overflow in computing interaction groups (openmm#4148)

erbad · Jul 21, 2023 · ae5bc67 · ae5bc67
1 parent dd07fa7
commit ae5bc67
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/platforms/common/src/kernels/customNonbondedGroups.cc b/platforms/common/src/kernels/customNonbondedGroups.cc
@@ -50,8 +50,9 @@ KERNEL void computeInteractionGroups(
     LOCAL AtomData localData[LOCAL_MEMORY_SIZE];
     LOCAL int reductionBuffer[LOCAL_MEMORY_SIZE];
 
-    const unsigned int startTile = (useNeighborList ? warp*numGroupTiles[0]/totalWarps : FIRST_TILE+warp*(LAST_TILE-FIRST_TILE)/totalWarps);
-    const unsigned int endTile = (useNeighborList ? (warp+1)*numGroupTiles[0]/totalWarps : FIRST_TILE+(warp+1)*(LAST_TILE-FIRST_TILE)/totalWarps);
+    mm_ulong wl = warp;
+    const unsigned int startTile = (unsigned int) (useNeighborList ? wl*numGroupTiles[0]/totalWarps : FIRST_TILE+wl*(LAST_TILE-FIRST_TILE)/totalWarps);
+    const unsigned int endTile = (unsigned int) (useNeighborList ? (wl+1)*numGroupTiles[0]/totalWarps : FIRST_TILE+(wl+1)*(LAST_TILE-FIRST_TILE)/totalWarps);
     for (int tile = startTile; tile < endTile; tile++) {
         const int4 atomData = groupData[TILE_SIZE*tile+tgx];
         const int atom1 = atomData.x;
@@ -155,8 +156,8 @@ KERNEL void buildNeighborList(GLOBAL int* RESTRICT rebuildNeighborList, GLOBAL i
     LOCAL volatile int tileIndex[WARPS_IN_BLOCK];
     LOCAL int reductionBuffer[LOCAL_MEMORY_SIZE];
 
-    const unsigned int startTile = warp*NUM_TILES/totalWarps;
-    const unsigned int endTile = (warp+1)*NUM_TILES/totalWarps;
+    const unsigned int startTile = (unsigned int) (warp*(mm_ulong)NUM_TILES/totalWarps);
+    const unsigned int endTile = (unsigned int) ((warp+1)*(mm_ulong)NUM_TILES/totalWarps);
     for (int tile = startTile; tile < endTile; tile++) {
         const int4 atomData = groupData[TILE_SIZE*tile+tgx];
         const int atom1 = atomData.x;