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36 * \brief Defines the constraint element for the modular simulator
38 * \author Pascal Merz <pascal.merz@me.com>
39 * \ingroup module_modularsimulator
44 #include "constraintelement.h"
46 #include "gromacs/math/vec.h"
47 #include "gromacs/mdtypes/enerdata.h"
48 #include "gromacs/mdtypes/inputrec.h"
49 #include "gromacs/mdtypes/state.h"
50 #include "gromacs/utility/fatalerror.h"
52 #include "energyelement.h"
53 #include "freeenergyperturbationelement.h"
54 #include "statepropagatordata.h"
58 template<ConstraintVariable variable>
59 ConstraintsElement<variable>::ConstraintsElement(Constraints* constr,
60 StatePropagatorData* statePropagatorData,
61 EnergyElement* energyElement,
62 FreeEnergyPerturbationElement* freeEnergyPerturbationElement,
65 const t_inputrec* inputrec,
66 const t_mdatoms* mdAtoms) :
67 nextVirialCalculationStep_(-1),
68 nextEnergyWritingStep_(-1),
69 nextLogWritingStep_(-1),
70 isMasterRank_(isMaster),
71 statePropagatorData_(statePropagatorData),
72 energyElement_(energyElement),
73 freeEnergyPerturbationElement_(freeEnergyPerturbationElement),
79 GMX_ASSERT(constr_, "Constraint element created but constr == nullptr");
82 template<ConstraintVariable variable>
83 void ConstraintsElement<variable>::elementSetup()
85 if (!inputrec_->bContinuation
86 && ((variable == ConstraintVariable::Positions && inputrec_->eI == eiMD)
87 || (variable == ConstraintVariable::Velocities && inputrec_->eI == eiVV)))
89 const real lambdaBonded = freeEnergyPerturbationElement_
90 ? freeEnergyPerturbationElement_->constLambdaView()[efptBONDED]
92 // Constrain the initial coordinates and velocities
93 do_constrain_first(fplog_, constr_, inputrec_, mdAtoms_, statePropagatorData_->localNumAtoms(),
94 statePropagatorData_->positionsView(), statePropagatorData_->velocitiesView(),
95 statePropagatorData_->box(), lambdaBonded);
99 if (inputrec_->eConstrAlg == econtLINCS)
101 fprintf(fplog_, "RMS relative constraint deviation after constraining: %.2e\n",
108 template<ConstraintVariable variable>
109 void ConstraintsElement<variable>::scheduleTask(Step step,
110 Time gmx_unused time,
111 const RegisterRunFunctionPtr& registerRunFunction)
113 bool calculateVirial = (step == nextVirialCalculationStep_);
114 bool writeLog = (step == nextLogWritingStep_);
115 bool writeEnergy = (step == nextEnergyWritingStep_);
117 // register constraining
118 (*registerRunFunction)(std::make_unique<SimulatorRunFunction>(
119 [this, step, calculateVirial, writeLog, writeEnergy]() {
120 apply(step, calculateVirial, writeLog, writeEnergy);
124 template<ConstraintVariable variable>
125 void ConstraintsElement<variable>::apply(Step step, bool calculateVirial, bool writeLog, bool writeEnergy)
129 ArrayRefWithPadding<RVec> x;
130 ArrayRefWithPadding<RVec> xprime;
131 ArrayRef<RVec> min_proj;
132 ArrayRefWithPadding<RVec> v;
134 const real lambdaBonded = freeEnergyPerturbationElement_
135 ? freeEnergyPerturbationElement_->constLambdaView()[efptBONDED]
141 case ConstraintVariable::Positions:
142 x = statePropagatorData_->previousPositionsView();
143 xprime = statePropagatorData_->positionsView();
144 v = statePropagatorData_->velocitiesView();
146 case ConstraintVariable::Velocities:
147 x = statePropagatorData_->positionsView();
148 xprime = statePropagatorData_->velocitiesView();
149 min_proj = statePropagatorData_->velocitiesView().unpaddedArrayRef();
151 default: gmx_fatal(FARGS, "Constraint algorithm not implemented for modular simulator.");
154 constr_->apply(writeLog, writeEnergy, step, 1, 1.0, x, xprime, min_proj, statePropagatorData_->box(),
155 lambdaBonded, &dvdlambda, v, calculateVirial ? &vir_con : nullptr, variable);
159 if (inputrec_->eI == eiVV)
161 // For some reason, the shake virial in VV is reset twice a step.
162 // Energy element will only do this once per step.
163 // TODO: Investigate this
164 clear_mat(energyElement_->constraintVirial(step));
166 energyElement_->addToConstraintVirial(vir_con, step);
169 /* The factor of 2 correction is necessary because half of the constraint
170 * force is removed in the VV step. This factor is either exact or a very
171 * good approximation, statistically insignificant in any real free energy
172 * calculation. Any possible error is not a simulation propagation error,
173 * but a potential reporting error in the data that goes to dh/dlambda.
176 const real c_dvdlConstraintCorrectionFactor = EI_VV(inputrec_->eI) ? 2.0 : 1.0;
177 energyElement_->enerdata()->term[F_DVDL_CONSTR] += c_dvdlConstraintCorrectionFactor * dvdlambda;
180 template<ConstraintVariable variable>
181 SignallerCallbackPtr ConstraintsElement<variable>::registerEnergyCallback(EnergySignallerEvent event)
183 if (event == EnergySignallerEvent::VirialCalculationStep)
185 return std::make_unique<SignallerCallback>(
186 [this](Step step, Time /*unused*/) { nextVirialCalculationStep_ = step; });
191 template<ConstraintVariable variable>
192 SignallerCallbackPtr ConstraintsElement<variable>::registerTrajectorySignallerCallback(TrajectoryEvent event)
194 if (event == TrajectoryEvent::EnergyWritingStep)
196 return std::make_unique<SignallerCallback>(
197 [this](Step step, Time /*unused*/) { nextEnergyWritingStep_ = step; });
202 template<ConstraintVariable variable>
203 SignallerCallbackPtr ConstraintsElement<variable>::registerLoggingCallback()
205 return std::make_unique<SignallerCallback>(
206 [this](Step step, Time /*unused*/) { nextLogWritingStep_ = step; });
209 //! Explicit template initialization
211 template class ConstraintsElement<ConstraintVariable::Positions>;
212 template class ConstraintsElement<ConstraintVariable::Velocities>;