Added NonbondedForce::getPMEParametersInContext()

platforms/opencl/tests/TestOpenCLEwald.cpp

@@ -42,6 +42,7 @@
 #include "openmm/LangevinIntegrator.h"
 #include "openmm/VerletIntegrator.h"
 #include "openmm/internal/ContextImpl.h"
+#include "openmm/internal/NonbondedForceImpl.h"
 #include "SimTKOpenMMRealType.h"
 #include "sfmt/SFMT.h"
 #include <iostream>
@@ -299,6 +300,19 @@ void testErrorTolerance(NonbondedForce::NonbondedMethod method) {
                 diff = sqrt(diff)/norm;
                 ASSERT(diff < 2*tol);
             }
+            if (method == NonbondedForce::PME) {
+                // See if the PME parameters were calculated correctly.
+
+                double expectedAlpha, actualAlpha;
+                int expectedSize[3], actualSize[3];
+                NonbondedForceImpl::calcPMEParameters(system, *force, expectedAlpha, expectedSize[0], expectedSize[1], expectedSize[2]);
+                force->getPMEParametersInContext(context, actualAlpha, actualSize[0], actualSize[1], actualSize[2]);
+                ASSERT_EQUAL_TOL(expectedAlpha, actualAlpha, 1e-5);
+                for (int i = 0; i < 3; i++) {
+                    ASSERT(actualSize[i] >= expectedSize[i]);
+                    ASSERT(actualSize[i] < expectedSize[i]+10);
+                }
+            }
         }
     }
 }

platforms/reference/include/ReferenceKernels.h

@@ -578,6 +578,15 @@ public:
      * @param force      the NonbondedForce to copy the parameters from
      */
     void copyParametersToContext(ContextImpl& context, const NonbondedForce& force);
+    /**
+     * Get the parameters being used for PME.
+     * 
+     * @param alpha   the separation parameter
+     * @param nx      the number of grid points along the X axis
+     * @param ny      the number of grid points along the Y axis
+     * @param nz      the number of grid points along the Z axis
+     */
+    void getPMEParameters(double& alpha, int& nx, int& ny, int& nz) const;
 private:
     int numParticles, num14;
     int **bonded14IndexArray;

platforms/reference/src/ReferenceKernels.cpp

@@ -969,6 +969,15 @@ void ReferenceCalcNonbondedForceKernel::copyParametersToContext(ContextImpl& con
         dispersionCoefficient = NonbondedForceImpl::calcDispersionCorrection(context.getSystem(), force);
 }
 
+void ReferenceCalcNonbondedForceKernel::getPMEParameters(double& alpha, int& nx, int& ny, int& nz) const {
+    if (nonbondedMethod != PME)
+        throw OpenMMException("getPMEParametersInContext: This Context is not using PME");
+    alpha = ewaldAlpha;
+    nx = gridSize[0];
+    ny = gridSize[1];
+    nz = gridSize[2];
+}
+
 ReferenceCalcCustomNonbondedForceKernel::~ReferenceCalcCustomNonbondedForceKernel() {
     disposeRealArray(particleParamArray, numParticles);
     if (neighborList != NULL)

platforms/reference/tests/TestReferenceEwald.cpp

@@ -42,6 +42,7 @@
 #include "SimTKOpenMMRealType.h"
 #include "sfmt/SFMT.h"
 #include "openmm/HarmonicBondForce.h"
+#include "openmm/internal/NonbondedForceImpl.h"
 #include <iostream>
 #include <vector>
 
@@ -397,6 +398,19 @@ void testErrorTolerance(NonbondedForce::NonbondedMethod method) {
                 diff = sqrt(diff)/norm;
                 ASSERT(diff < 2*tol);
             }
+            if (method == NonbondedForce::PME) {
+                // See if the PME parameters were calculated correctly.
+
+                double expectedAlpha, actualAlpha;
+                int expectedSize[3], actualSize[3];
+                NonbondedForceImpl::calcPMEParameters(system, *force, expectedAlpha, expectedSize[0], expectedSize[1], expectedSize[2]);
+                force->getPMEParametersInContext(context, actualAlpha, actualSize[0], actualSize[1], actualSize[2]);
+                ASSERT_EQUAL_TOL(expectedAlpha, actualAlpha, 1e-5);
+                for (int i = 0; i < 3; i++) {
+                    ASSERT(actualSize[i] >= expectedSize[i]);
+                    ASSERT(actualSize[i] < expectedSize[i]+10);
+                }
+            }
         }
     }
 }

plugins/cpupme/src/CpuPmeKernels.cpp

@@ -583,6 +583,13 @@ bool CpuCalcPmeReciprocalForceKernel::isProcessorSupported() {
     return isVec4Supported();
 }
 
+void CpuCalcPmeReciprocalForceKernel::getPMEParameters(double& alpha, int& nx, int& ny, int& nz) const {
+    alpha = this->alpha;
+    nx = gridx;
+    ny = gridy;
+    nz = gridz;
+}
+
 int CpuCalcPmeReciprocalForceKernel::findFFTDimension(int minimum, bool isZ) {
     if (minimum < 1)
         return 1;

plugins/cpupme/src/CpuPmeKernels.h

@@ -91,6 +91,15 @@ public:
      * Get whether the current CPU supports all features needed by this kernel.
      */
     static bool isProcessorSupported();
+    /**
+     * Get the parameters being used for PME.
+     * 
+     * @param alpha   the separation parameter
+     * @param nx      the number of grid points along the X axis
+     * @param ny      the number of grid points along the Y axis
+     * @param nz      the number of grid points along the Z axis
+     */
+    void getPMEParameters(double& alpha, int& nx, int& ny, int& nz) const;
 private:
     class ComputeTask;
     /**