#ifndef OPENMM_AMOEBA_ANGLE_FORCE_H_ #define OPENMM_AMOEBA_ANGLE_FORCE_H_ /* -------------------------------------------------------------------------- * * OpenMMAmoeba * * -------------------------------------------------------------------------- * * 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: Mark Friedrichs, 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 "openmm/Force.h" #include "internal/windowsExportAmoeba.h" #include namespace OpenMM { /** * This class implements an interaction between triplets of particles that varies with the angle * between them. The interaction is defined by a 6th order polynomial. Only the quadratic term * is set per-angle. The coefficients of the higher order terms each have a single value that * is set globally. * * To use it, create an AmoebaAngleForce object then call addAngle() once for each angle. After * an angle has been added, you can modify its force field parameters by calling setAngleParameters(). * This will have no effect on Contexts that already exist unless you call updateParametersInContext(). */ class OPENMM_EXPORT_AMOEBA AmoebaAngleForce : public Force { public: /** * Create an AmoebaAngleForce. */ AmoebaAngleForce(); /** * Get the number of angle stretch terms in the potential function */ int getNumAngles() const { return angles.size(); } /** * Set the global cubic term * * @param cubicK the cubic force constant for the angle */ void setAmoebaGlobalAngleCubic(double cubicK); /** * Get the global cubic term * * @return global cubicK term */ double getAmoebaGlobalAngleCubic() const; /** * Set the global quartic term * * @param quarticK the quartic force constant for the angle */ void setAmoebaGlobalAngleQuartic(double quarticK); /** * Get the global quartic term * * @return global quartic term */ double getAmoebaGlobalAngleQuartic() const; /** * Set the global pentic term * * @param penticK the pentic force constant for the angle */ void setAmoebaGlobalAnglePentic(double penticK); /** * Get the global pentic term * * @return global penticK term */ double getAmoebaGlobalAnglePentic() const; /** * Set the global sextic term * * @param sexticK the sextic force constant for the angle */ void setAmoebaGlobalAngleSextic(double sexticK); /** * Get the global sextic term * * @return global sextic term */ double getAmoebaGlobalAngleSextic() const; /** * Add an angle term to the force field. * * @param particle1 the index of the first particle connected by the angle * @param particle2 the index of the second particle connected by the angle * @param particle3 the index of the third particle connected by the angle * @param length the equilibrium angle, measured in degrees * @param quadraticK the quadratic force constant for the angle, measured in kJ/mol/radian^2 * @return the index of the angle that was added */ int addAngle(int particle1, int particle2, int particle3, double length, double quadraticK); /** * Get the force field parameters for an angle term. * * @param index the index of the angle for which to get parameters * @param[out] particle1 the index of the first particle connected by the angle * @param[out] particle2 the index of the second particle connected by the angle * @param[out] particle3 the index of the third particle connected by the angle * @param[out] length the equilibrium angle, measured in degrees * @param[out] quadraticK the quadratic force constant for the angle, measured in kJ/mol/radian^2 */ void getAngleParameters(int index, int& particle1, int& particle2, int& particle3, double& length, double& quadraticK) const; /** * Set the force field parameters for an angle term. * * @param index the index of the angle for which to set parameters * @param particle1 the index of the first particle connected by the angle * @param particle2 the index of the second particle connected by the angle * @param particle3 the index of the third particle connected by the angle * @param length the equilibrium angle, measured in degrees * @param quadraticK the quadratic force constant for the angle, measured in kJ/mol/radian^2 */ void setAngleParameters(int index, int particle1, int particle2, int particle3, double length, double quadraticK); /** * Update the per-angle 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 setAngleParameters() 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-angle parameters. The set of particles involved * in an angle cannot be changed, nor can new angles 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; double _globalCubicK, _globalQuarticK, _globalPenticK, _globalSexticK; private: class AngleInfo; std::vector angles; bool usePeriodic; }; /** * This is an internal class used to record information about an angle. * @private */ class AmoebaAngleForce::AngleInfo { public: int particle1, particle2, particle3; double length, quadraticK; AngleInfo() { particle1 = particle2 = particle3 = -1; length = quadraticK = 0.0; } AngleInfo(int particle1, int particle2, int particle3, double length, double quadraticK) : particle1(particle1), particle2(particle2), particle3(particle3), length(length), quadraticK(quadraticK) { } }; } // namespace OpenMM #endif /*OPENMM_AMOEBA_ANGLE_FORCE_H_*/