Fixed a bug in random number generation for the CUDA platform. Updated test cases.

platforms/cuda/src/kernels/gpu.cpp

@@ -869,7 +869,7 @@ int gpuAllocateInitialBuffers(gpuContext gpu)
     gpu->seed                           = 1;
     gpu->sim.randomFrames               = 20;
     gpu->sim.randomIterations           = gpu->sim.randomFrames;
-    gpu->sim.randoms                    = gpu->sim.randomFrames * gpu->sim.paddedNumberOfAtoms - 5 * GRID;
+    gpu->sim.randoms                    = gpu->sim.randomFrames * gpu->sim.paddedNumberOfAtoms;
     gpu->sim.totalRandoms               = gpu->sim.randoms + gpu->sim.paddedNumberOfAtoms;
     gpu->sim.totalRandomsTimesTwo       = gpu->sim.totalRandoms * 2;
     gpu->psRandom4                      = new CUDAStream<float4>(gpu->sim.totalRandomsTimesTwo, 1, "Random4");

platforms/cuda/tests/TestCudaBrownianIntegrator.cpp

@@ -121,7 +121,7 @@ void testTemperature() {
     }
     pe /= steps;
     double expected = 0.5*numBonds*BOLTZ*temp;
-    ASSERT_EQUAL_TOL(expected, pe, 20*expected/std::sqrt((double) steps));
+    ASSERT_EQUAL_TOL(expected, pe, 0.1*expected);
 }
 
 void testConstraints() {

platforms/reference/src/SimTKReference/ReferenceRigidShakeAlgorithm.cpp

@@ -499,15 +499,15 @@ RealOpenMM damping = one;//(RealOpenMM) (iterations%2 == 0 ? 0.5 : 1.0);
          }
       }
    }
-   static int sum = 0;
-   static int count = 0;
-   sum += iterations;
-   count++;
-   if (count == 100) {
-       printf("%d iterations\n", sum);
-       sum = 0;
-       count = 0;
-   }
+//   static int sum = 0;
+//   static int count = 0;
+//   sum += iterations;
+//   count++;
+//   if (count == 100) {
+//       printf("%d iterations\n", sum);
+//       sum = 0;
+//       count = 0;
+//   }
 
    // diagnostics
 

platforms/reference/tests/TestReferenceBrownianIntegrator.cpp

@@ -119,7 +119,7 @@ void testTemperature() {
     }
     pe /= steps;
     double expected = 0.5*numBonds*BOLTZ*temp;
-    ASSERT_EQUAL_TOL(expected, pe, 20*expected/std::sqrt((double) steps));
+    ASSERT_EQUAL_TOL(expected, pe, 0.1*expected);
 }
 
 void testConstraints() {