Global parameters defined by CustomNonbondedForce can have default values

openmmapi/include/openmm/CustomNonbondedForce.h

@@ -187,9 +187,10 @@ public:
      * Add a new global parmeter that the interaction may depend on.
      *
      * @param name             the name of the parameter
+     * @param defaultValue     the default value of the parameter
      * @return the index of the parameter that was added
      */
-    int addGlobalParameter(const std::string& name);
+    int addGlobalParameter(const std::string& name, double defaultValue);
     /**
      * Get the name of a global parameter.
      *
@@ -204,6 +205,20 @@ public:
      * @param name           the name of the parameter
      */
     void setGlobalParameterName(int index, const std::string& name);
+    /**
+     * Get the default value of a global parameter.
+     *
+     * @param index     the index of the parameter for which to get the default value
+     * @return the parameter default value
+     */
+    double getGlobalParameterDefaultValue(int index) const;
+    /**
+     * Set the default value of a global parameter.
+     *
+     * @param index          the index of the parameter for which to set the default value
+     * @param name           the default value of the parameter
+     */
+    void setGlobalParameterDefaultValue(int index, double defaultValue);
     /**
      * Add the nonbonded force parameters for a particle.  This should be called once for each particle
      * in the System.  When it is called for the i'th time, it specifies the parameters for the i'th particle.
@@ -263,13 +278,14 @@ protected:
 private:
     class ParticleInfo;
     class ParameterInfo;
+    class GlobalParameterInfo;
     class ExceptionInfo;
     NonbondedMethod nonbondedMethod;
     double cutoffDistance;
     Vec3 periodicBoxVectors[3];
     std::string energyExpression;
     std::vector<ParameterInfo> parameters;
-    std::vector<std::string> globalParameters;
+    std::vector<GlobalParameterInfo> globalParameters;
     std::vector<ParticleInfo> particles;
     std::vector<ExceptionInfo> exceptions;
     std::map<std::pair<int, int>, int> exceptionMap;
@@ -293,6 +309,16 @@ public:
     }
 };
 
+class CustomNonbondedForce::GlobalParameterInfo {
+public:
+    std::string name;
+    double defaultValue;
+    GlobalParameterInfo() {
+    }
+    GlobalParameterInfo(const std::string& name, double defaultValue) : name(name), defaultValue(defaultValue) {
+    }
+};
+
 class CustomNonbondedForce::ExceptionInfo {
 public:
     int particle1, particle2;

openmmapi/include/openmm/Force.h

@@ -55,7 +55,7 @@ class ForceImpl;
 
 class OPENMM_EXPORT Force {
 public:
-	Force() {}
+    Force() {}
     virtual ~Force() {
     }
 protected:
@@ -68,8 +68,8 @@ protected:
     virtual ForceImpl* createImpl() = 0;
     
 private:
-	Force& operator=(const Force& rhs);
-	Force(const Force& rhs);
+    Force& operator=(const Force& rhs);
+    Force(const Force& rhs);
 };
 
 } // namespace OpenMM

openmmapi/src/CustomNonbondedForce.cpp

@@ -115,17 +115,25 @@ void CustomNonbondedForce::setParameterCombiningRule(int index, const string& co
     parameters[index].combiningRule = combiningRule;
 }
 
-int CustomNonbondedForce::addGlobalParameter(const string& name) {
-    globalParameters.push_back(name);
+int CustomNonbondedForce::addGlobalParameter(const string& name, double defaultValue) {
+    globalParameters.push_back(GlobalParameterInfo(name, defaultValue));
     return globalParameters.size()-1;
 }
 
 const string& CustomNonbondedForce::getGlobalParameterName(int index) const {
-    return globalParameters[index];
+    return globalParameters[index].name;
 }
 
 void CustomNonbondedForce::setGlobalParameterName(int index, const string& name) {
-    globalParameters[index] = name;
+    globalParameters[index].name = name;
+}
+
+double CustomNonbondedForce::getGlobalParameterDefaultValue(int index) const {
+    return globalParameters[index].defaultValue;
+}
+
+void CustomNonbondedForce::setGlobalParameterDefaultValue(int index, double defaultValue) {
+    globalParameters[index].defaultValue = defaultValue;
 }
 
 int CustomNonbondedForce::addParticle(const vector<double>& parameters) {

openmmapi/src/CustomNonbondedForceImpl.cpp

@@ -121,6 +121,6 @@ vector<string> CustomNonbondedForceImpl::getKernelNames() {
 map<string, double> CustomNonbondedForceImpl::getDefaultParameters() {
     map<string, double> parameters;
     for (int i = 0; i < owner.getNumGlobalParameters(); i++)
-        parameters[owner.getGlobalParameterName(i)] = 0.0;
+        parameters[owner.getGlobalParameterName(i)] = owner.getGlobalParameterDefaultValue(i);
     return parameters;
 }

platforms/reference/tests/TestReferenceCustomNonbondedForce.cpp

@@ -80,8 +80,8 @@ void testParameters() {
     CustomNonbondedForce* forceField = new CustomNonbondedForce("scale*a*(r*b)^3");
     forceField->addParameter("a", "a1*a2");
     forceField->addParameter("b", "c+b1+b2");
-    forceField->addGlobalParameter("scale");
-    forceField->addGlobalParameter("c");
+    forceField->addGlobalParameter("scale", 3.0);
+    forceField->addGlobalParameter("c", -1.0);
     vector<double> params(2);
     params[0] = 1.5;
     params[1] = 2.0;