Reduced memory use for random numbers. Also reduced the frequency of reordering water molecules.

platforms/cuda/src/CudaKernels.cpp

@@ -47,7 +47,7 @@ using namespace std;
 
 static void calcForces(OpenMMContextImpl& context, CudaPlatform::PlatformData& data) {
     _gpuContext* gpu = data.gpu;
-    if (data.stepCount%100 == 0)
+    if (data.stepCount%200 == 0)
         gpuReorderAtoms(gpu);
     data.stepCount++;
     kClearForces(gpu);

platforms/cuda/src/kernels/gpu.cpp

@@ -1198,7 +1198,7 @@ int gpuAllocateInitialBuffers(gpuContext gpu)
     gpu->psAtomIndex->Upload();
     // Determine randoms
     gpu->seed                           = 1;
-    gpu->sim.randomFrames               = 95;
+    gpu->sim.randomFrames               = 20;
     gpu->sim.randomIterations           = gpu->sim.randomFrames;
     gpu->sim.randoms                    = gpu->sim.randomFrames * gpu->sim.paddedNumberOfAtoms - 5 * GRID;
     gpu->sim.totalRandoms               = gpu->sim.randoms + gpu->sim.paddedNumberOfAtoms;

platforms/cuda/tests/TestCudaRandom.cpp

@@ -48,7 +48,7 @@ static const float RGAS                     =    BOLTZMANN * AVOGADRO;     // (J
 static const float BOLTZ                    =    (RGAS / KILO);            // (kJ/(mol K)) 
 
 void testGaussian() {
-    _gpuContext* gpu = (_gpuContext*) gpuInit(1000);
+    _gpuContext* gpu = (_gpuContext*) gpuInit(5000);
     gpu->sim.Yv = 1.0;
     gpu->sim.Yx = 1.0;
     gpu->sim.V = 1.0;