#ifndef OPENMM_RBTORSIONFORCE_H_ #define OPENMM_RBTORSIONFORCE_H_ /* -------------------------------------------------------------------------- * * OpenMM * * -------------------------------------------------------------------------- * * This is part of the OpenMM molecular simulation toolkit originating from * * Simbios, the NIH National Center for Physics-Based Simulation of * * Biological Structures at Stanford, funded under the NIH Roadmap for * * Medical Research, grant U54 GM072970. See https://simtk.org. * * * * Portions copyright (c) 2008-2016 Stanford University and the Authors. * * Authors: Peter Eastman * * Contributors: * * * * Permission is hereby granted, free of charge, to any person obtaining a * * copy of this software and associated documentation files (the "Software"), * * to deal in the Software without restriction, including without limitation * * the rights to use, copy, modify, merge, publish, distribute, sublicense, * * and/or sell copies of the Software, and to permit persons to whom the * * Software is furnished to do so, subject to the following conditions: * * * * The above copyright notice and this permission notice shall be included in * * all copies or substantial portions of the Software. * * * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * * THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * * USE OR OTHER DEALINGS IN THE SOFTWARE. * * -------------------------------------------------------------------------- */ #include "Force.h" #include "Vec3.h" #include #include #include "internal/windowsExport.h" namespace OpenMM { /** * This class implements an interaction between groups of four particles that varies with the torsion angle between them * according to the Ryckaert-Bellemans potential. To use it, create an RBTorsionForce object then call addTorsion() once * for each torsion. After a torsion has been added, you can modify its force field parameters by calling setTorsionParameters(). * This will have no effect on Contexts that already exist unless you call updateParametersInContext(). */ class OPENMM_EXPORT RBTorsionForce : public Force { public: /** * Create a RBTorsionForce. */ RBTorsionForce(); /** * Get the number of Ryckaert-Bellemans torsion terms in the potential function */ int getNumTorsions() const; /** * Add a Ryckaert-Bellemans torsion term to the force field. * * @param particle1 the index of the first particle forming the torsion * @param particle2 the index of the second particle forming the torsion * @param particle3 the index of the third particle forming the torsion * @param particle4 the index of the fourth particle forming the torsion * @param c0 the coefficient of the constant term, measured in kJ/mol * @param c1 the coefficient of the 1st order term, measured in kJ/mol * @param c2 the coefficient of the 2nd order term, measured in kJ/mol * @param c3 the coefficient of the 3rd order term, measured in kJ/mol * @param c4 the coefficient of the 4th order term, measured in kJ/mol * @param c5 the coefficient of the 5th order term, measured in kJ/mol * @return the index of the torsion that was added */ 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. * * @param index the index of the torsion for which to get parameters * @param[out] particle1 the index of the first particle forming the torsion * @param[out] particle2 the index of the second particle forming the torsion * @param[out] particle3 the index of the third particle forming the torsion * @param[out] particle4 the index of the fourth particle forming the torsion * @param[out] c0 the coefficient of the constant term, measured in kJ/mol * @param[out] c1 the coefficient of the 1st order term, measured in kJ/mol * @param[out] c2 the coefficient of the 2nd order term, measured in kJ/mol * @param[out] c3 the coefficient of the 3rd order term, measured in kJ/mol * @param[out] c4 the coefficient of the 4th order term, measured in kJ/mol * @param[out] c5 the coefficient of the 5th order term, measured in kJ/mol */ void getTorsionParameters(int index, int& particle1, int& particle2, int& particle3, int& particle4, double& c0, double& c1, double& c2, double& c3, double& c4, double& c5) const; /** * Set the force field parameters for a Ryckaert-Bellemans torsion term. * * @param index the index of the torsion for which to set parameters * @param particle1 the index of the first particle forming the torsion * @param particle2 the index of the second particle forming the torsion * @param particle3 the index of the third particle forming the torsion * @param particle4 the index of the fourth particle forming the torsion * @param c0 the coefficient of the constant term, measured in kJ/mol * @param c1 the coefficient of the 1st order term, measured in kJ/mol * @param c2 the coefficient of the 2nd order term, measured in kJ/mol * @param c3 the coefficient of the 3rd order term, measured in kJ/mol * @param c4 the coefficient of the 4th order term, measured in kJ/mol * @param c5 the coefficient of the 5th order term, measured in kJ/mol */ void setTorsionParameters(int index, int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5); /** * Update the per-torsion parameters in a Context to match those stored in this Force object. This method provides * an efficient method to update certain parameters in an existing Context without needing to reinitialize it. * Simply call setTorsionParameters() to modify this object's parameters, then call updateParametersInContext() * to copy them over to the Context. * * The only information this method updates is the values of per-torsion parameters. The set of particles involved * in a torsion cannot be changed, nor can new torsions be added. */ void updateParametersInContext(Context& context); /** * Set whether this force should apply periodic boundary conditions when calculating displacements. * Usually this is not appropriate for bonded forces, but there are situations when it can be useful. */ void setUsesPeriodicBoundaryConditions(bool periodic); /** * Returns whether or not this force makes use of periodic boundary * conditions. * * @returns true if force uses PBC and false otherwise */ bool usesPeriodicBoundaryConditions() const; protected: ForceImpl* createImpl() const; private: class RBTorsionInfo; std::vector rbTorsions; bool usePeriodic; }; /** * This is an internal class used to record information about a torsion. * @private */ class RBTorsionForce::RBTorsionInfo { public: int particle1, particle2, particle3, particle4; double c[6]; RBTorsionInfo() { particle1 = particle2 = particle3 = particle4 = -1; c[0] = c[1] = c[2] = c[3] = c[4] = c[5] = 0.0; } RBTorsionInfo(int particle1, int particle2, int particle3, int particle4, double c0, double c1, double c2, double c3, double c4, double c5) : particle1(particle1), particle2(particle2), particle3(particle3), particle4(particle4) { c[0] = c0; c[1] = c1; c[2] = c2; c[3] = c3; c[4] = c4; c[5] = c5; } }; } // namespace OpenMM #endif /*OPENMM_RBTORSIONFORCE_H_*/