Merge pull request #650 from peastman/opt

Optimizations to AMOEBA

plugins/amoeba/platforms/cuda/src/kernels/multipoleInducedField.cu

@@ -87,17 +87,13 @@ __device__ void computeOneInteraction(AtomData& atom1, AtomData& atom2, real3 de
         real scale3 = 1;
         real scale5 = 1;
         real damp = atom1.damp*atom2.damp;
-        if (damp != 0) {
         real ratio = (r/damp);
         ratio = ratio*ratio*ratio;
         float pgamma = atom1.thole < atom2.thole ? atom1.thole : atom2.thole;
-            damp = -pgamma*ratio;
-            if (damp > -50) {
+        damp = damp == 0 ? 0 : -pgamma*ratio;
         real expdamp = EXP(damp);
         scale3 = 1 - expdamp;
         scale5 = 1 - expdamp*(1-damp);
-            }
-        }
         real dsc3 = scale3;
         real dsc5 = scale5;
         real r3 = (r*r2);

plugins/amoeba/platforms/cuda/src/kernels/pmeElectrostaticPairForce.cu

@@ -211,7 +211,6 @@ computeOneInteractionF2NoScale(
         real pgamma = atom1.thole < atom2.thole ? atom1.thole : atom2.thole;
         real ratio = RECIP(rr1*damp);
         damp = -pgamma*ratio*ratio*ratio;
-        damp = damp < -50 ? 0 : damp;
     }
 
     real scale5 = (damp == 0) ? 1 : (1 - (1-damp)*EXP(damp));
@@ -358,8 +357,7 @@ computeOneInteractionF2NoScale(
     ftm22 += gfi1*yr;
     ftm23 += gfi1*zr;
 
-    if (damp != 0) {
-
+    {
         real expdamp = EXP(damp);
         real temp3 = -1.5f*damp*expdamp*rr1*rr1;
         real temp5 = -damp;
@@ -556,8 +554,7 @@ computeOneInteractionF2NoScale(
     ftm22 += gfi1*yr;
     ftm23 += gfi1*zr;
 
-    if (damp != 0) {
-
+    {
         real expdamp = EXP(damp);
         real temp3 = -1.5f*damp*expdamp*rr1*rr1;
         real temp5 = -damp;

plugins/amoeba/platforms/cuda/src/kernels/pmeElectrostaticPairForceNoQuadrupoles.cu

@@ -129,7 +129,6 @@ computeOneInteractionF2NoScale(
         real pgamma = atom1.thole < atom2.thole ? atom1.thole : atom2.thole;
         real ratio = RECIP(rr1*damp);
         damp = -pgamma*ratio*ratio*ratio;
-        damp = damp < -50 ? 0 : damp;
     }
 
     real scale5 = (damp == 0) ? 1 : (1 - (1-damp)*EXP(damp));
@@ -232,8 +231,7 @@ computeOneInteractionF2NoScale(
     ftm22 += gfi1*yr;
     ftm23 += gfi1*zr;
 
-    if (damp != 0) {
-
+    {
         real expdamp = EXP(damp);
         real temp3 = -1.5f*damp*expdamp*rr1*rr1;
         real temp5 = -damp;
@@ -376,8 +374,7 @@ computeOneInteractionF2NoScale(
     ftm22 += gfi1*yr;
     ftm23 += gfi1*zr;
 
-    if (damp != 0) {
-
+    {
         real expdamp = EXP(damp);
         real temp3 = -1.5f*damp*expdamp*rr1*rr1;
         real temp5 = -damp;