Softcore factor multiplying LJ eps is now lambda^4 instead of lambda^1

Removed references to softCoreLJLambda in NonbondedSoftcoreForce

plugins/freeEnergy/openmmapi/include/openmm/NonbondedSoftcoreForce.h

@@ -132,15 +132,6 @@ public:
      * is NoCutoff, this value will have no effect.
      */
     void setCutoffDistance(double distance);
-    /**
-     * Get the soft-core LJ lambda (in nm) being used for nonbonded interactions.
-     * is NoCutoff, this value will have no effect.
-     */
-    double getSoftCoreLJLambda(void) const;
-    /**
-     * Set the soft core LJ lambda (in nm) being used for nonbonded interactions.
-     */
-    void setSoftCoreLJLambda(double lambda);
     /**
      * Get the error tolerance for Ewald summation.  This corresponds to the fractional error in the forces
      * which is acceptable.  This value is used to select the reciprocal space cutoff and separation
@@ -283,7 +274,7 @@ private:
     class ParticleInfo;
     class ExceptionInfo;
     NonbondedSoftcoreMethod nonbondedMethod;
-    double cutoffDistance, rfDielectric,  ewaldErrorTol, softCoreLJLambda;
+    double cutoffDistance, rfDielectric,  ewaldErrorTol;
     void addExclusionsToSet(const std::vector<std::set<int> >& bonded12, std::set<int>& exclusions, int baseParticle, int fromParticle, int currentLevel) const;
 
 // Retarded visual studio compiler complains about being unable to 

plugins/freeEnergy/openmmapi/src/NonbondedSoftcoreForce.cpp

@@ -46,7 +46,7 @@ using std::string;
 using std::stringstream;
 using std::vector;
 
-NonbondedSoftcoreForce::NonbondedSoftcoreForce() : nonbondedMethod(NoCutoff), cutoffDistance(1.0),  rfDielectric(78.3), ewaldErrorTol(1e-4), softCoreLJLambda(1.0) {
+NonbondedSoftcoreForce::NonbondedSoftcoreForce() : nonbondedMethod(NoCutoff), cutoffDistance(1.0),  rfDielectric(78.3), ewaldErrorTol(1e-4) {
 }
 
 NonbondedSoftcoreForce::NonbondedSoftcoreMethod NonbondedSoftcoreForce::getNonbondedMethod() const {
@@ -65,14 +65,6 @@ void NonbondedSoftcoreForce::setCutoffDistance(double distance) {
     cutoffDistance = distance;
 }
 
-double NonbondedSoftcoreForce::getSoftCoreLJLambda( void ) const {
-    return softCoreLJLambda;
-}
-
-void NonbondedSoftcoreForce::setSoftCoreLJLambda(double lambda) {
-    softCoreLJLambda = lambda;
-}
-
 double NonbondedSoftcoreForce::getReactionFieldDielectric( void ) const {
     return rfDielectric;
 }

plugins/freeEnergy/platforms/cuda/src/CudaFreeEnergyKernelFactory.cpp

@@ -48,16 +48,19 @@ using namespace OpenMM;
 
 extern "C" void initOpenMMCudaFreeEnergyPlugin() {
 
+//(void) fprintf( stderr, "initOpenMMCudaFreeEnergyPlugin called ");
     if ( gpuIsAvailable() ){
         CudaPlatform* cudaPlatform            = new CudaPlatform();
         CudaFreeEnergyKernelFactory* factory  = new CudaFreeEnergyKernelFactory();
     
+//(void) fprintf( stderr, "gpu is available platform=%p", cudaPlatform);
         cudaPlatform->registerKernelFactory(CalcNonbondedSoftcoreForceKernel::Name(), factory);
         cudaPlatform->registerKernelFactory(CalcGBSAOBCSoftcoreForceKernel::Name(), factory);
         cudaPlatform->registerKernelFactory(CalcGBVISoftcoreForceKernel::Name(), factory);
     
         Platform::registerPlatform(cudaPlatform);
     }
+//(void) fprintf( stderr, "\n");
 }
 
 KernelImpl* CudaFreeEnergyKernelFactory::createKernelImpl(std::string name, const Platform& platform, ContextImpl& context) const {

plugins/freeEnergy/platforms/cuda/src/kernels/kSoftcoreLJ.h

@@ -37,7 +37,8 @@ __device__ float getSoftCoreLJ( float r2, float sig, float  eps, float lambdaI,
 
    float r                         = sqrt(r2);
    float lambda                    = lambdaI < lambdaJ ? lambdaI : lambdaJ;
-   eps                            *= lambda;
+   float lambda2                   = lambda*lambda;
+   eps                            *= lambda2*lambda2;
 
 
     // (r/sig)

plugins/freeEnergy/platforms/reference/src/ReferenceFreeEnergyKernelFactory.cpp

@@ -54,9 +54,9 @@
 using namespace OpenMM;
 
 extern "C" void initOpenMMReferenceFreeEnergyPlugin() {
-
     ReferencePlatform* referencePlatform       = new ReferencePlatform();
 
+//(void) fprintf( stderr, "In initOpenMMReferenceFreeEnergyPlugin platform=%p\n", referencePlatform );
     ReferenceFreeEnergyKernelFactory* factory  = new ReferenceFreeEnergyKernelFactory();
     referencePlatform->registerKernelFactory(CalcNonbondedSoftcoreForceKernel::Name(), factory);
     referencePlatform->registerKernelFactory(CalcGBSAOBCSoftcoreForceKernel::Name(), factory);

plugins/freeEnergy/platforms/reference/src/SimTKReference/ReferenceFreeEnergyLJCoulombSoftcoreIxn.cpp

@@ -951,6 +951,7 @@ int ReferenceFreeEnergyLJCoulombSoftcoreIxn::calculateOneSoftCoreLJIxn( RealOpen
 
     static const RealOpenMM zero        =  0.0;
     static const RealOpenMM one         =  1.0;
+    static const RealOpenMM four        =  4.0;
     static const RealOpenMM six         =  6.0;
     static const RealOpenMM twelve      = 12.0;
     static const RealOpenMM alphaLJ     = 0.5;
@@ -964,7 +965,7 @@ calculateOneLJIxn( one/r, sig, eps, &dEdROrig, &E_Orig );
 
     // soft-core LJ energy = lambda*4*eps*[ 1/{alphaLJ*(1-lambda) + (r/sig)**6}**2 - 1/{alphaLJ*(1-lambda) + (r/sig)**6} ]
 
-    eps                                *= lambda;
+    eps                                *= POW( lambda, four );
 
     RealOpenMM sig2                     = r/sig;
                sig2                    *= sig2;