Minor optimization to PME (#5151)

* Minor optimization to PME * Minor simplification

Minor optimization to PME (#5151)
* Minor optimization to PME * Minor simplification
b0c2c4d8 · Peter Eastman · GitHub · a112fbfc · b0c2c4d8
Unverified Commit b0c2c4d8 authored Dec 01, 2025 by Peter Eastman Committed by GitHub Dec 01, 2025
Show whitespace changes
Inline Side-by-side

Showing with 8 additions and 6 deletions

platforms/common/src/kernels/pme.cc platforms/common/src/kernels/pme.cc +8 -6

No files found.
--- a/platforms/common/src/kernels/pme.cc
+++ b/platforms/common/src/kernels/pme.cc
@@ -102,6 +102,7 @@ KERNEL void gridSpreadCharge(GLOBAL const real4* RESTRICT posq,
                ybase = ybase*GRID_SIZE_Z;
                int index = xbase + ybase + zindex;
                real add = dzdx*data[iy].y;
+                if (fabs(add) > 2.3e-10f) { // Smallest value representable in 64 bit fixed point
 #ifdef USE_FIXED_POINT_CHARGE_SPREADING
                    ATOMIC_ADD(&pmeGrid[index], (mm_ulong) realToFixedPoint(add));
 #if defined(__GFX12__)
@@ -116,6 +117,7 @@ KERNEL void gridSpreadCharge(GLOBAL const real4* RESTRICT posq,
                }
            }
        }
+    }
 }

 #ifdef USE_FIXED_POINT_CHARGE_SPREADING