Reduced the cost of updating tabulated functions (#3649)

openmmapi/include/openmm/TabulatedFunction.h

@@ -9,7 +9,7 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2014 Stanford University and the Authors.           *
+ * Portions copyright (c) 2014-2022 Stanford University and the Authors.      *
  * Authors: Peter Eastman                                                     *
  * Contributors:                                                              *
  *                                                                            *
@@ -57,6 +57,8 @@ namespace OpenMM {
 
 class OPENMM_EXPORT TabulatedFunction {
 public:
+    TabulatedFunction() : updateCount(0) {
+    }
     virtual ~TabulatedFunction() {
     }
     /**
@@ -67,12 +69,18 @@ public:
      * Get the periodicity status of the tabulated function.
      */
     bool getPeriodic() const;
+    /**
+     * Get the value of a counter that is updated every time setFunctionParameters()
+     * is called.  This provides a fast way to detect when a function has changed.
+     */
+    int getUpdateCount() const;
     virtual bool operator==(const TabulatedFunction& other) const = 0;
     virtual bool operator!=(const TabulatedFunction& other) const {
         return !(*this == other);
     }
 protected:
     bool periodic;
+    int updateCount;
 };
 
 /**

openmmapi/src/TabulatedFunction.cpp

@@ -6,7 +6,7 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2014-2021 Stanford University and the Authors.      *
+ * Portions copyright (c) 2014-2022 Stanford University and the Authors.      *
  * Authors: Peter Eastman                                                     *
  * Contributors:                                                              *
  *                                                                            *
@@ -39,6 +39,10 @@ bool TabulatedFunction::getPeriodic() const {
     return periodic;
 }
 
+int TabulatedFunction::getUpdateCount() const {
+    return updateCount;
+}
+
 Continuous1DFunction::Continuous1DFunction(const vector<double>& values, double min, double max, bool periodic) {
     this->periodic = periodic;
     setFunctionParameters(values, min, max);
@@ -66,6 +70,7 @@ void Continuous1DFunction::setFunctionParameters(const vector<double>& values, d
     this->values = values;
     this->min = min;
     this->max = max;
+    updateCount++;
 }
 
 Continuous1DFunction* Continuous1DFunction::Copy() const {
@@ -120,6 +125,7 @@ void Continuous2DFunction::setFunctionParameters(int xsize, int ysize, const vec
     this->xmax = xmax;
     this->ymin = ymin;
     this->ymax = ymax;
+    updateCount++;
 }
 
 Continuous2DFunction* Continuous2DFunction::Copy() const {
@@ -186,6 +192,7 @@ void Continuous3DFunction::setFunctionParameters(int xsize, int ysize, int zsize
     this->ymax = ymax;
     this->zmin = zmin;
     this->zmax = zmax;
+    updateCount++;
 }
 
 Continuous3DFunction* Continuous3DFunction::Copy() const {
@@ -220,6 +227,7 @@ void Discrete1DFunction::getFunctionParameters(vector<double>& values) const {
 
 void Discrete1DFunction::setFunctionParameters(const vector<double>& values) {
     this->values = values;
+    updateCount++;
 }
 
 Discrete1DFunction* Discrete1DFunction::Copy() const {
@@ -256,6 +264,7 @@ void Discrete2DFunction::setFunctionParameters(int xsize, int ysize, const vecto
     this->xsize = xsize;
     this->ysize = ysize;
     this->values = values;
+    updateCount++;
 }
 
 Discrete2DFunction* Discrete2DFunction::Copy() const {
@@ -297,6 +306,7 @@ void Discrete3DFunction::setFunctionParameters(int xsize, int ysize, int zsize,
     this->ysize = ysize;
     this->zsize = zsize;
     this->values = values;
+    updateCount++;
 }
 
 Discrete3DFunction* Discrete3DFunction::Copy() const {

platforms/common/include/openmm/common/CommonKernels.h

@@ -530,7 +530,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     const System& system;
 };
 
@@ -579,7 +579,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     std::vector<void*> groupForcesArgs;
     ComputeKernel computeCentersKernel, groupForcesKernel, applyForcesKernel;
     const System& system;
@@ -632,7 +632,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     std::vector<std::string> paramNames, computedValueNames;
     std::vector<ComputeParameterInfo> paramBuffers, computedValueBuffers;
     double longRangeCoefficient;
@@ -735,7 +735,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     std::vector<bool> pairValueUsesParam, pairEnergyUsesParam, pairEnergyUsesValue;
     const System& system;
     ComputeKernel pairValueKernel, perParticleValueKernel, pairEnergyKernel, perParticleEnergyKernel, gradientChainRuleKernel;
@@ -793,7 +793,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     const System& system;
     ComputeKernel donorKernel, acceptorKernel;
 };
@@ -845,7 +845,7 @@ private:
     std::vector<std::string> globalParamNames;
     std::vector<float> globalParamValues;
     std::vector<ComputeArray> tabulatedFunctionArrays;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     const System& system;
     ComputeKernel forceKernel, blockBoundsKernel, neighborsKernel, startIndicesKernel, copyPairsKernel;
     ComputeEvent event;

platforms/common/src/CommonKernels.cpp

@@ -35,7 +35,6 @@
 #include "openmm/internal/CustomCompoundBondForceImpl.h"
 #include "openmm/internal/CustomHbondForceImpl.h"
 #include "openmm/internal/CustomManyParticleForceImpl.h"
-#include "openmm/serialization/XmlSerializer.h"
 #include "CommonKernelSources.h"
 #include "lepton/CustomFunction.h"
 #include "lepton/ExpressionTreeNode.h"
@@ -1294,7 +1293,7 @@ void CommonCalcCustomCompoundBondForceKernel::initialize(const System& system, c
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
         int width;
         vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
@@ -1417,8 +1416,8 @@ void CommonCalcCustomCompoundBondForceKernel::copyParametersToContext(ContextImp
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);
@@ -1553,7 +1552,7 @@ void CommonCalcCustomCentroidBondForceKernel::initialize(const System& system, c
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         string arrayName = "table"+cc.intToString(i);
         functionDefinitions.push_back(make_pair(name, arrayName));
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
@@ -1747,8 +1746,8 @@ void CommonCalcCustomCentroidBondForceKernel::copyParametersToContext(ContextImp
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);
@@ -1902,7 +1901,7 @@ void CommonCalcCustomNonbondedForceKernel::initialize(const System& system, cons
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         string arrayName = prefix+"table"+cc.intToString(i);
         functionDefinitions.push_back(make_pair(name, arrayName));
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
@@ -2459,8 +2458,8 @@ void CommonCalcCustomNonbondedForceKernel::copyParametersToContext(ContextImpl&
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);
@@ -2798,7 +2797,7 @@ void CommonCalcCustomGBForceKernel::initialize(const System& system, const Custo
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         string arrayName = prefix+"table"+cc.intToString(i);
         functionDefinitions.push_back(make_pair(name, arrayName));
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
@@ -3785,8 +3784,8 @@ void CommonCalcCustomGBForceKernel::copyParametersToContext(ContextImpl& context
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);
@@ -4012,7 +4011,7 @@ void CommonCalcCustomHbondForceKernel::initialize(const System& system, const Cu
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         string arrayName = "table"+cc.intToString(i);
         functionDefinitions.push_back(make_pair(name, arrayName));
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
@@ -4336,8 +4335,8 @@ void CommonCalcCustomHbondForceKernel::copyParametersToContext(ContextImpl& cont
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);
@@ -4425,7 +4424,7 @@ void CommonCalcCustomManyParticleForceKernel::initialize(const System& system, c
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         functionList.push_back(&force.getTabulatedFunction(i));
         string name = force.getTabulatedFunctionName(i);
-        tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
         string arrayName = "table"+cc.intToString(i);
         functionDefinitions.push_back(make_pair(name, arrayName));
         functions[name] = cc.getExpressionUtilities().getFunctionPlaceholder(force.getTabulatedFunction(i));
@@ -4855,8 +4854,8 @@ void CommonCalcCustomManyParticleForceKernel::copyParametersToContext(ContextImp
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             int width;
             vector<float> f = cc.getExpressionUtilities().computeFunctionCoefficients(force.getTabulatedFunction(i), width);
             tabulatedFunctionArrays[i].upload(f);

platforms/cpu/include/CpuKernels.h

@@ -334,7 +334,7 @@ private:
     std::vector<std::string> parameterNames, globalParameterNames, computedValueNames, energyParamDerivNames;
     std::vector<std::pair<std::set<int>, std::set<int> > > interactionGroups;
     std::vector<double> longRangeCoefficientDerivs;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
     CpuCustomNonbondedForce* nonbonded;
 };
@@ -424,7 +424,7 @@ private:
     std::vector<std::string> particleParameterNames, globalParameterNames, energyParamDerivNames, valueNames;
     std::vector<OpenMM::CustomGBForce::ComputationType> valueTypes;
     std::vector<OpenMM::CustomGBForce::ComputationType> energyTypes;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
 };
 
@@ -467,7 +467,7 @@ private:
     std::vector<std::vector<double> > particleParamArray;
     CpuCustomManyParticleForce* ixn;
     std::vector<std::string> globalParameterNames;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
 };
 

platforms/cpu/src/CpuKernels.cpp

@@ -45,7 +45,6 @@
 #include "openmm/internal/ContextImpl.h"
 #include "openmm/internal/NonbondedForceImpl.h"
 #include "openmm/internal/vectorize.h"
-#include "openmm/serialization/XmlSerializer.h"
 #include "lepton/CompiledExpression.h"
 #include "lepton/CustomFunction.h"
 #include "lepton/Operation.h"
@@ -888,10 +887,10 @@ void CpuCalcCustomNonbondedForceKernel::initialize(const System& system, const C
         switchingDistance = force.getSwitchingDistance();
     }
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Record information for the long range correction.
 
@@ -1053,8 +1052,8 @@ void CpuCalcCustomNonbondedForceKernel::copyParametersToContext(ContextImpl& con
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1166,10 +1165,10 @@ void CpuCalcCustomGBForceKernel::initialize(const System& system, const CustomGB
         neighborList = new CpuNeighborList(4);
     data.isPeriodic |= (force.getNonbondedMethod() == CustomGBForce::CutoffPeriodic);
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
 
@@ -1319,8 +1318,8 @@ void CpuCalcCustomGBForceKernel::copyParametersToContext(ContextImpl& context, c
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1349,10 +1348,10 @@ void CpuCalcCustomManyParticleForceKernel::initialize(const System& system, cons
     for (int i = 0; i < force.getNumGlobalParameters(); i++)
         globalParameterNames.push_back(force.getGlobalParameterName(i));
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
 
@@ -1399,8 +1398,8 @@ void CpuCalcCustomManyParticleForceKernel::copyParametersToContext(ContextImpl&
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }

platforms/reference/include/ReferenceKernels.h

@@ -706,7 +706,7 @@ private:
     std::vector<std::string> parameterNames, globalParameterNames, computedValueNames, energyParamDerivNames;
     std::vector<std::pair<std::set<int>, std::set<int> > > interactionGroups;
     std::vector<double> longRangeCoefficientDerivs;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
     NeighborList* neighborList;
 };
@@ -797,7 +797,7 @@ private:
     std::vector<std::vector<Lepton::CompiledExpression> > energyGradientExpressions;
     std::vector<std::vector<Lepton::CompiledExpression> > energyParamDerivExpressions;
     std::vector<OpenMM::CustomGBForce::ComputationType> energyTypes;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
     NeighborList* neighborList;
 };
@@ -884,7 +884,7 @@ private:
     ReferenceCustomHbondIxn* ixn;
     std::vector<std::set<int> > exclusions;
     std::vector<std::string> globalParameterNames;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
 };
 
 /**
@@ -927,7 +927,7 @@ private:
     std::vector<std::vector<double> > bondParamArray;
     ReferenceCustomCentroidBondIxn* ixn;
     std::vector<std::string> globalParameterNames, energyParamDerivNames;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     bool usePeriodic;
     Vec3* boxVectors;
 };
@@ -970,7 +970,7 @@ private:
     std::vector<std::vector<double> > bondParamArray;
     ReferenceCustomCompoundBondIxn* ixn;
     std::vector<std::string> globalParameterNames, energyParamDerivNames;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     bool usePeriodic;
     Vec3* boxVectors;
 };
@@ -1012,7 +1012,7 @@ private:
     std::vector<std::vector<double> > particleParamArray;
     ReferenceCustomManyParticleIxn* ixn;
     std::vector<std::string> globalParameterNames;
-    std::map<std::string, const TabulatedFunction*> tabulatedFunctions;
+    std::map<std::string, int> tabulatedFunctionUpdateCount;
     NonbondedMethod nonbondedMethod;
 };
 

platforms/reference/src/ReferenceKernels.cpp

@@ -80,7 +80,6 @@
 #include "openmm/internal/NonbondedForceImpl.h"
 #include "openmm/Integrator.h"
 #include "openmm/OpenMMException.h"
-#include "openmm/serialization/XmlSerializer.h"
 #include "SimTKOpenMMUtilities.h"
 #include "lepton/CustomFunction.h"
 #include "lepton/Operation.h"
@@ -1177,10 +1176,10 @@ void ReferenceCalcCustomNonbondedForceKernel::initialize(const System& system, c
         switchingDistance = force.getSwitchingDistance();
     }
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the expressions.
     
@@ -1349,8 +1348,8 @@ void ReferenceCalcCustomNonbondedForceKernel::copyParametersToContext(ContextImp
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1465,10 +1464,10 @@ void ReferenceCalcCustomGBForceKernel::initialize(const System& system, const Cu
     else
         neighborList = new NeighborList();
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the expressions.
     
@@ -1624,8 +1623,8 @@ void ReferenceCalcCustomGBForceKernel::copyParametersToContext(ContextImpl& cont
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1750,10 +1749,10 @@ void ReferenceCalcCustomHbondForceKernel::initialize(const System& system, const
         globalParameterNames.push_back(force.getGlobalParameterName(i));
     nonbondedCutoff = force.getCutoffDistance();
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
     
@@ -1839,8 +1838,8 @@ void ReferenceCalcCustomHbondForceKernel::copyParametersToContext(ContextImpl& c
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1873,10 +1872,10 @@ void ReferenceCalcCustomCentroidBondForceKernel::initialize(const System& system
     for (int i = 0; i < numBonds; ++i)
         force.getBondParameters(i, bondGroups[i], bondParamArray[i]);
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
     
@@ -1962,8 +1961,8 @@ void ReferenceCalcCustomCentroidBondForceKernel::copyParametersToContext(Context
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -1990,10 +1989,10 @@ void ReferenceCalcCustomCompoundBondForceKernel::initialize(const System& system
     for (int i = 0; i < numBonds; ++i)
         force.getBondParameters(i, bondParticles[i], bondParamArray[i]);
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
 
@@ -2078,8 +2077,8 @@ void ReferenceCalcCustomCompoundBondForceKernel::copyParametersToContext(Context
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }
@@ -2107,10 +2106,10 @@ void ReferenceCalcCustomManyParticleForceKernel::initialize(const System& system
     for (int i = 0; i < force.getNumGlobalParameters(); i++)
         globalParameterNames.push_back(force.getGlobalParameterName(i));
 
-    // Record the tabulated functions for future reference.
+    // Record the tabulated function update counts for future reference.
 
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++)
-        tabulatedFunctions[force.getTabulatedFunctionName(i)] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        tabulatedFunctionUpdateCount[force.getTabulatedFunctionName(i)] = force.getTabulatedFunction(i).getUpdateCount();
 
     // Create the interaction.
 
@@ -2158,8 +2157,8 @@ void ReferenceCalcCustomManyParticleForceKernel::copyParametersToContext(Context
     bool changed = false;
     for (int i = 0; i < force.getNumTabulatedFunctions(); i++) {
         string name = force.getTabulatedFunctionName(i);
-        if (force.getTabulatedFunction(i) != *tabulatedFunctions[name]) {
-            tabulatedFunctions[name] = XmlSerializer::clone(force.getTabulatedFunction(i));
+        if (force.getTabulatedFunction(i).getUpdateCount() != tabulatedFunctionUpdateCount[name]) {
+            tabulatedFunctionUpdateCount[name] = force.getTabulatedFunction(i).getUpdateCount();
             changed = true;
         }
     }