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36 /*! \libinternal \file
39 * This file contains the definition of a container for force and virial
42 * Currently the only container defined here is one used in algorithms
43 * that provide their own virial tensor contribution.
44 * We can consider adding another containter for forces and shift forces.
49 * \ingroup module_mdtypes
52 #ifndef GMX_MDTYPES_FORCEOUTPUT_H
53 #define GMX_MDTYPES_FORCEOUTPUT_H
55 #include "gromacs/math/arrayrefwithpadding.h"
56 #include "gromacs/math/vectypes.h"
57 #include "gromacs/utility/arrayref.h"
62 /*! \libinternal \brief Container for force and virial for algorithms that compute shift forces for virial calculation
64 * This force output class should be used when computing forces whos virial contribution
65 * is computed using the "single sum virial" algorithm (see the reference manual for
66 * details). To handle the virial contributions of forces working between periodic
67 * images correctly, so-called "shift forces" need to be accumulated for the different
70 class ForceWithShiftForces
73 /*! \brief Constructor
75 * \param[in] force A force buffer that will be used for storing forces
76 * \param[in] computeVirial True when algorithms are required to provide their virial contribution (for the current force evaluation)
77 * \param[in] shiftForces A shift forces buffer of size SHIFTS, also needed with \p computeVirial = false
79 ForceWithShiftForces(const gmx::ArrayRefWithPadding<gmx::RVec> &force,
80 const bool computeVirial,
81 const gmx::ArrayRef<gmx::RVec> &shiftForces) :
83 computeVirial_(computeVirial),
84 shiftForces_(shiftForces) {}
86 //! Returns an arrayref to the force buffer without padding
87 gmx::ArrayRef<gmx::RVec> force()
89 return force_.unpaddedArrayRef();
92 //! Returns a const arrayref to the force buffer without padding
93 gmx::ArrayRef<const gmx::RVec> force() const
95 return force_.unpaddedConstArrayRef();
98 //! Returns whether the virial needs to be computed
99 bool computeVirial() const
101 return computeVirial_;
104 //! Returns the shift forces buffer
105 gmx::ArrayRef<gmx::RVec> shiftForces()
110 //! Returns a const shift forces buffer
111 gmx::ArrayRef<const gmx::RVec> shiftForces() const
118 gmx::ArrayRefWithPadding<gmx::RVec> force_;
119 //! True when virial computation is requested
121 //! A buffer for storing the shift forces, size SHIFTS
122 gmx::ArrayRef<gmx::RVec> shiftForces_;
125 /*! \libinternal \brief Container for force and virial for algorithms that provide their own virial tensor contribution
127 * \note The \p force_ data member is a reference to an external force buffer.
129 class ForceWithVirial
132 /*! \brief Constructor
134 * \param[in] force A force buffer that will be used for storing forces
135 * \param[in] computeVirial True when algorithms are required to provide their virial contribution (for the current force evaluation)
137 ForceWithVirial(const ArrayRef<RVec> &force,
138 const bool computeVirial) :
140 computeVirial_(computeVirial)
142 for (int dim1 = 0; dim1 < DIM; dim1++)
144 for (int dim2 = 0; dim2 < DIM; dim2++)
146 virial_[dim1][dim2] = 0;
151 /*! \brief Adds a virial contribution
153 * \note Can be called with \p computeVirial=false.
154 * \note It is recommended to accumulate the virial contributions
155 * of a module internally before calling this method, as that
156 * will reduce rounding errors.
158 * \param[in] virial The virial contribution to add
160 void addVirialContribution(const matrix virial)
164 for (int dim1 = 0; dim1 < DIM; dim1++)
166 for (int dim2 = 0; dim2 < DIM; dim2++)
168 virial_[dim1][dim2] += virial[dim1][dim2];
174 /*! \brief Adds a virial diagonal contribution
176 * \note Can be called with \p computeVirial=false.
177 * \note It is recommended to accumulate the virial contributions
178 * of a module internally before calling this method, as that
179 * will reduce rounding errors.
181 * \param[in] virial The virial contribution to add
183 void addVirialContribution(const RVec virial)
187 for (int dim = 0; dim < DIM; dim++)
189 virial_[dim][dim] += virial[dim];
194 /*! \brief Returns the accumulated virial contributions
196 const matrix &getVirial() const
201 const ArrayRef<RVec> force_; //!< Force accumulation buffer reference
202 const bool computeVirial_; //!< True when algorithms are required to provide their virial contribution (for the current force evaluation)
204 matrix virial_; //!< Virial accumulation buffer
207 /*! \libinternal \brief Force and virial output buffers for use in force computation
213 ForceOutputs(const ForceWithShiftForces &forceWithShiftForces,
214 const ForceWithVirial &forceWithVirial) :
215 forceWithShiftForces_(forceWithShiftForces),
216 forceWithVirial_(forceWithVirial) {}
218 //! Returns a reference to the force with shift forces object
219 ForceWithShiftForces &forceWithShiftForces()
221 return forceWithShiftForces_;
224 //! Returns a reference to the force with virial object
225 ForceWithVirial &forceWithVirial()
227 return forceWithVirial_;
231 //! Force output buffer used by legacy modules (without SIMD padding)
232 ForceWithShiftForces forceWithShiftForces_;
233 //! Force with direct virial contribution (if there are any; without SIMD padding)
234 ForceWithVirial forceWithVirial_;