Modified some stochastic test cases to fail less often

platforms/cuda/tests/TestCudaAndersenThermostat.cpp

@@ -54,9 +54,9 @@ void testTemperature() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 5000;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.003);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -70,6 +70,7 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
@@ -81,20 +82,20 @@ void testTemperature() {
     for (int i = 0; i < numSteps; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
-        integrator.step(1);
+        integrator.step(10);
     }
     ke /= numSteps;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testConstraints() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 15000;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.004);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -122,10 +123,11 @@ void testConstraints() {
     positions[6] = Vec3(0, 1, 1);
     positions[7] = Vec3(0, 0, 1);
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
@@ -137,7 +139,7 @@ void testConstraints() {
     }
     ke /= numSteps;
     double expected = 0.5*(numParticles*3-system.getNumConstraints())*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testRandomSeed() {

platforms/cuda/tests/TestCudaVariableLangevinIntegrator.cpp

@@ -99,7 +99,7 @@ void testTemperature() {
     const int numParticles = 8;
     const double temp = 100.0;
     System system;
-    VariableLangevinIntegrator integrator(temp, 5.0, 1e-4);
+    VariableLangevinIntegrator integrator(temp, 5.0, 5e-5);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -111,20 +111,21 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
     double ke = 0.0;
-    for (int i = 0; i < 1000; ++i) {
+    for (int i = 0; i < 5000; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
         integrator.step(5);
     }
-    ke /= 1000;
+    ke /= 5000;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
@@ -276,13 +277,13 @@ void testArgonBox() {
     // Make sure the temperature is correct.
     
     double ke = 0.0;
-    for (int i = 0; i < 400; ++i) {
+    for (int i = 0; i < 2000; ++i) {
         double t = 2.0 + 0.01 * (i + 1);
         integrator.stepTo(t);
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
     }
-    ke /= 400;
+    ke /= 2000;
     double expected = 1.5 * numParticles * BOLTZ * temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.01);
 }

platforms/opencl/tests/TestOpenCLAndersenThermostat.cpp

@@ -54,9 +54,9 @@ void testTemperature() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 5000;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.003);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -70,6 +70,7 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
@@ -81,20 +82,20 @@ void testTemperature() {
     for (int i = 0; i < numSteps; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
-        integrator.step(1);
+        integrator.step(10);
     }
     ke /= numSteps;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testConstraints() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 15000;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.004);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -122,10 +123,11 @@ void testConstraints() {
     positions[6] = Vec3(0, 1, 1);
     positions[7] = Vec3(0, 0, 1);
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
@@ -137,7 +139,7 @@ void testConstraints() {
     }
     ke /= numSteps;
     double expected = 0.5*(numParticles*3-system.getNumConstraints())*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testRandomSeed() {

platforms/opencl/tests/TestOpenCLVariableLangevinIntegrator.cpp

@@ -99,7 +99,7 @@ void testTemperature() {
     const int numParticles = 8;
     const double temp = 100.0;
     System system;
-    VariableLangevinIntegrator integrator(temp, 5.0, 1e-4);
+    VariableLangevinIntegrator integrator(temp, 5.0, 5e-5);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -111,20 +111,21 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
     double ke = 0.0;
-    for (int i = 0; i < 1000; ++i) {
+    for (int i = 0; i < 5000; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
         integrator.step(5);
     }
-    ke /= 1000;
+    ke /= 5000;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
@@ -276,13 +277,13 @@ void testArgonBox() {
     // Make sure the temperature is correct.
     
     double ke = 0.0;
-    for (int i = 0; i < 400; ++i) {
+    for (int i = 0; i < 2000; ++i) {
         double t = 2.0 + 0.01 * (i + 1);
         integrator.stepTo(t);
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
     }
-    ke /= 400;
+    ke /= 2000;
     double expected = 1.5 * numParticles * BOLTZ * temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.01);
 }

platforms/reference/tests/TestReferenceAndersenThermostat.cpp

@@ -52,10 +52,10 @@ void testTemperature() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 5000;
     ReferencePlatform platform;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.003);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -69,6 +69,7 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
     
     // Let it equilibrate.
     
@@ -80,21 +81,21 @@ void testTemperature() {
     for (int i = 0; i < numSteps; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
-        integrator.step(1);
+        integrator.step(10);
     }
     ke /= numSteps;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testConstraints() {
     const int numParticles = 8;
     const double temp = 100.0;
     const double collisionFreq = 10.0;
-    const int numSteps = 10000;
+    const int numSteps = 15000;
     ReferencePlatform platform;
     System system;
-    VerletIntegrator integrator(0.005);
+    VerletIntegrator integrator(0.004);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -122,10 +123,11 @@ void testConstraints() {
     positions[6] = Vec3(0, 1, 1);
     positions[7] = Vec3(0, 0, 1);
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
@@ -137,7 +139,7 @@ void testConstraints() {
     }
     ke /= numSteps;
     double expected = 0.5*(numParticles*3-system.getNumConstraints())*BOLTZ*temp;
-    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 6/std::sqrt((double) numSteps));
+    ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
 
 void testRandomSeed() {

platforms/reference/tests/TestReferenceVariableLangevinIntegrator.cpp

@@ -99,7 +99,7 @@ void testTemperature() {
     const double temp = 100.0;
     ReferencePlatform platform;
     System system;
-    VariableLangevinIntegrator integrator(temp, 5.0, 1e-4);
+    VariableLangevinIntegrator integrator(temp, 5.0, 5e-5);
     NonbondedForce* forceField = new NonbondedForce();
     for (int i = 0; i < numParticles; ++i) {
         system.addParticle(2.0);
@@ -111,20 +111,21 @@ void testTemperature() {
     for (int i = 0; i < numParticles; ++i)
         positions[i] = Vec3((i%2 == 0 ? 2 : -2), (i%4 < 2 ? 2 : -2), (i < 4 ? 2 : -2));
     context.setPositions(positions);
+    context.setVelocitiesToTemperature(temp);
 
     // Let it equilibrate.
 
-    integrator.step(10000);
+    integrator.step(5000);
 
     // Now run it for a while and see if the temperature is correct.
 
     double ke = 0.0;
-    for (int i = 0; i < 1000; ++i) {
+    for (int i = 0; i < 5000; ++i) {
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
         integrator.step(5);
     }
-    ke /= 1000;
+    ke /= 5000;
     double expected = 0.5*numParticles*3*BOLTZ*temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.1);
 }
@@ -279,13 +280,13 @@ void testArgonBox() {
     // Make sure the temperature is correct.
     
     double ke = 0.0;
-    for (int i = 0; i < 400; ++i) {
+    for (int i = 0; i < 2000; ++i) {
         double t = 2.0 + 0.01 * (i + 1);
         integrator.stepTo(t);
         State state = context.getState(State::Energy);
         ke += state.getKineticEnergy();
     }
-    ke /= 400;
+    ke /= 2000;
     double expected = 1.5 * numParticles * BOLTZ * temp;
     ASSERT_USUALLY_EQUAL_TOL(expected, ke, 0.01);
 }