The various addX() methods return the index of the thing they just added

openmmapi/include/openmm/GBSAOBCForce.h

@@ -70,8 +70,9 @@ public:
      * @param charge         the charge of the particle, measured in units of the proton charge
      * @param radius         the GBSA radius of the particle, measured in nm
      * @param scalingFactor  the OBC scaling factor for the particle
+     * @return the index of the particle that was added
      */
-    void addParticle(double charge, double radius, double scalingFactor);
+    int addParticle(double charge, double radius, double scalingFactor);
     /**
      * Get the force field parameters for a particle.
      * 

openmmapi/include/openmm/GBVIForce.h

@@ -70,8 +70,9 @@ public:
      * @param charge         the charge of the particle, measured in units of the proton charge
      * @param radius         the GB/VI radius of the particle, measured in nm
      * @param gamma          the gamma parameter
+     * @return the index of the particle that was added
      */
-    void addParticle(double charge, double radius, double gamma);
+    int addParticle(double charge, double radius, double gamma);
     /**
      * Get the force field parameters for a particle.
      * 

openmmapi/include/openmm/HarmonicAngleForce.h

@@ -66,8 +66,9 @@ public:
      * @param particle3 the index of the third particle forming the angle
      * @param angle     the equilibrium angle, measured in radians
      * @param k         the harmonic force constant for the angle
+     * @return the index of the angle that was added
      */
-    void addAngle(int particle1, int particle2, int particle3, double angle, double k);
+    int addAngle(int particle1, int particle2, int particle3, double angle, double k);
     /**
      * Get the force field parameters for an angle term.
      * 

openmmapi/include/openmm/HarmonicBondForce.h

@@ -65,8 +65,9 @@ public:
      * @param particle2 the index of the second particle connected by the bond
      * @param length    the equilibrium length of the bond, measured in nm
      * @param k         the harmonic force constant for the bond
+     * @return the index of the bond that was added
      */
-    void addBond(int particle1, int particle2, double length, double k);
+    int addBond(int particle1, int particle2, double length, double k);
     /**
      * Get the force field parameters for a bond term.
      * 

openmmapi/include/openmm/NonbondedForce.h

@@ -161,8 +161,9 @@ public:
      * @param charge    the charge of the particle, measured in units of the proton charge
      * @param sigma     the sigma parameter of the Lennard-Jones potential (corresponding to the van der Waals radius of the particle), measured in nm
      * @param epsilon   the epsilon parameter of the Lennard-Jones potential (corresponding to the well depth of the van der Waals interaction), measured in kJ/mol
+     * @return the index of the particle that was added
      */
-    void addParticle(double charge, double sigma, double epsilon);
+    int addParticle(double charge, double sigma, double epsilon);
     /**
      * Get the nonbonded force parameters for a particle.
      *
@@ -195,8 +196,9 @@ public:
      * @param chargeProd the scaled product of the atomic charges (i.e. the strength of the Coulomb interaction), measured in units of the proton charge squared
      * @param sigma      the sigma parameter of the Lennard-Jones potential (corresponding to the van der Waals radius of the particle), measured in nm
      * @param epsilon    the epsilon parameter of the Lennard-Jones potential (corresponding to the well depth of the van der Waals interaction), measured in kJ/mol
+     * @return the index of the exception that was added
      */
-    void addException(int particle1, int particle2, double chargeProd, double sigma, double epsilon);
+    int addException(int particle1, int particle2, double chargeProd, double sigma, double epsilon);
     /**
      * Get the force field parameters for an interaction that should be calculated differently from others.
      * 

openmmapi/include/openmm/PeriodicTorsionForce.h

@@ -68,8 +68,9 @@ public:
      * @param periodicity  the periodicity of the torsion
      * @param phase        the phase offset of the torsion, measured in radians
      * @param k            the force constant for the torsion
+     * @return the index of the torsion that was added
      */
-    void addTorsion(int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k);
+    int addTorsion(int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k);
     /**
      * Get the force field parameters for a periodic torsion term.
      * 

openmmapi/include/openmm/RBTorsionForce.h

@@ -71,8 +71,9 @@ public:
      * @param c3           the coefficient of the 3rd order term
      * @param c4           the coefficient of the 4th order term
      * @param c5           the coefficient of the 5th order term
+     * @return the index of the torsion that was added
      */
-    void addTorsion(int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5);
+    int addTorsion(int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5);
     /**
      * Get the force field parameters for a Ryckaert-Bellemans torsion term.
      * 

openmmapi/include/openmm/System.h

@@ -72,9 +72,11 @@ public:
      * Add a particle to the System.
      *
      * @param mass   the mass of the particle (in atomic mass units)
+     * @return the index of the particle that was added
      */
-    void addParticle(double mass) {
+    int addParticle(double mass) {
         masses.push_back(mass);
+        return masses.size()-1;
     }
     /**
      * Get the mass (in atomic mass units) of a particle.
@@ -105,8 +107,9 @@ public:
      * @param particle1 the index of the first particle involved in the constraint
      * @param particle2 the index of the second particle involved in the constraint
      * @param distance  the required distance between the two particles, measured in nm
+     * @return the index of the constraint that was added
      */
-    void addConstraint(int particle1, int particle2, double distance);
+    int addConstraint(int particle1, int particle2, double distance);
     /**
      * Get the parameters defining a distance constraint.
      * 

openmmapi/src/GBSAOBCForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 GBSAOBCForce::GBSAOBCForce() : solventDielectric(78.3), soluteDielectric(1.0) {
 }
 
-void GBSAOBCForce::addParticle(double charge, double radius, double scalingFactor) {
+int GBSAOBCForce::addParticle(double charge, double radius, double scalingFactor) {
     particles.push_back(ParticleInfo(charge, radius, scalingFactor));
+    return particles.size()-1;
 }
 
 void GBSAOBCForce::getParticleParameters(int index, double& charge, double& radius, double& scalingFactor) const {

openmmapi/src/GBVIForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 GBVIForce::GBVIForce() : solventDielectric(78.3), soluteDielectric(1.0) {
 }
 
-void GBVIForce::addParticle(double charge, double radius, double gamma) {
+int GBVIForce::addParticle(double charge, double radius, double gamma) {
     particles.push_back(ParticleInfo(charge, radius, gamma));
+    return particles.size()-1;
 }
 
 void GBVIForce::getParticleParameters(int index, double& charge, double& radius, double& gamma) const {

openmmapi/src/HarmonicAngleForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 HarmonicAngleForce::HarmonicAngleForce() {
 }
 
-void HarmonicAngleForce::addAngle(int particle1, int particle2, int particle3, double angle, double k) {
+int HarmonicAngleForce::addAngle(int particle1, int particle2, int particle3, double angle, double k) {
     angles.push_back(AngleInfo(particle1, particle2, particle3, angle, k));
+    return angles.size()-1;
 }
 
 void HarmonicAngleForce::getAngleParameters(int index, int& particle1, int& particle2, int& particle3, double& angle, double& k) const {

openmmapi/src/HarmonicBondForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 HarmonicBondForce::HarmonicBondForce() {
 }
 
-void HarmonicBondForce::addBond(int particle1, int particle2, double length, double k) {
+int HarmonicBondForce::addBond(int particle1, int particle2, double length, double k) {
     bonds.push_back(BondInfo(particle1, particle2, length, k));
+    return bonds.size()-1;
 }
 
 void HarmonicBondForce::getBondParameters(int index, int& particle1, int& particle2, double& length, double& k) const {

openmmapi/src/NonbondedForce.cpp

@@ -81,8 +81,9 @@ void NonbondedForce::setPeriodicBoxVectors(Vec3 a, Vec3 b, Vec3 c) {
     periodicBoxVectors[2] = c;
 }
 
-void NonbondedForce::addParticle(double charge, double sigma, double epsilon) {
+int NonbondedForce::addParticle(double charge, double sigma, double epsilon) {
     particles.push_back(ParticleInfo(charge, sigma, epsilon));
+    return particles.size()-1;
 }
 
 void NonbondedForce::getParticleParameters(int index, double& charge, double& sigma, double& epsilon) const {
@@ -97,8 +98,9 @@ void NonbondedForce::setParticleParameters(int index, double charge, double sigm
     particles[index].epsilon = epsilon;
 }
 
-void NonbondedForce::addException(int particle1, int particle2, double chargeProd, double sigma, double epsilon) {
+int NonbondedForce::addException(int particle1, int particle2, double chargeProd, double sigma, double epsilon) {
     exceptions.push_back(ExceptionInfo(particle1, particle2, chargeProd, sigma, epsilon));
+    return exceptions.size()-1;
 }
 void NonbondedForce::getExceptionParameters(int index, int& particle1, int& particle2, double& chargeProd, double& sigma, double& epsilon) const {
     particle1 = exceptions[index].particle1;

openmmapi/src/PeriodicTorsionForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 PeriodicTorsionForce::PeriodicTorsionForce() {
 }
 
-void PeriodicTorsionForce::addTorsion(int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k) {
+int PeriodicTorsionForce::addTorsion(int particle1, int particle2, int particle3, int particle4, int periodicity, double phase, double k) {
     periodicTorsions.push_back(PeriodicTorsionInfo(particle1, particle2, particle3, particle4, periodicity, phase, k));
+    return periodicTorsions.size()-1;
 }
 
 void PeriodicTorsionForce::getTorsionParameters(int index, int& particle1, int& particle2, int& particle3, int& particle4, int& periodicity, double& phase, double& k) const {

openmmapi/src/RBTorsionForce.cpp

@@ -39,8 +39,9 @@ using namespace OpenMM;
 RBTorsionForce::RBTorsionForce() {
 }
 
-void RBTorsionForce::addTorsion(int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5) {
+int RBTorsionForce::addTorsion(int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5) {
     rbTorsions.push_back(RBTorsionInfo(particle1, particle2, particle3, particle4, c0, c1, c2, c3, c4, c5));
+    return rbTorsions.size()-1;
 }
 
 void RBTorsionForce::getTorsionParameters(int index, int& particle1, int& particle2, int& particle3, int& particle4, double& c0, double& c1, double& c2, double& c3, double& c4, double& c5) const {

openmmapi/src/System.cpp

@@ -42,8 +42,9 @@ System::~System() {
         delete forces[i];
 }
 
-void System::addConstraint(int particle1, int particle2, double distance) {
+int System::addConstraint(int particle1, int particle2, double distance) {
     constraints.push_back(ConstraintInfo(particle1, particle2, distance));
+    return constraints.size()-1;
 }
 
 void System::getConstraintParameters(int index, int& particle1, int& particle2, double& distance) const {