Line data Source code
1 : // Copyright (C) 2015 Technische Universitaet Muenchen
2 : // This file is part of the Mamico project. For conditions of distribution
3 : // and use, please see the copyright notice in Mamico's main folder, or at
4 : // www5.in.tum.de/mamico
5 : #ifndef _MOLECULARDYNAMICS_COUPLING_CONFIGURATIONS_PARTICLEINSERTIONCONFIGURATION_H_
6 : #define _MOLECULARDYNAMICS_COUPLING_CONFIGURATIONS_PARTICLEINSERTIONCONFIGURATION_H_
7 :
8 : #include "coupling/NoParticleInsertion.h"
9 : #include "coupling/UsherParticleInsertion.h"
10 : #include "coupling/interface/MDSolverInterface.h"
11 : #include "tarch/configuration/Configuration.h"
12 : #include "tarch/configuration/ParseConfiguration.h"
13 : #include "tarch/la/Vector.h"
14 : #include <iostream>
15 :
16 : namespace coupling {
17 : namespace configurations {
18 : class ParticleInsertionConfiguration;
19 : }
20 : } // namespace coupling
21 :
22 : /** configuration for particle insertion algorithm (e.g.: USHER). Derive from
23 : *the class tarch::configuration::Configuration
24 : * @brief configuration for particle insertion algorithm (e.g.: USHER).
25 : * @tparam dim Number of dimensions; it can be 1, 2 or 3
26 : * @author Philipp Neumann
27 : */
28 : class coupling::configurations::ParticleInsertionConfiguration : public tarch::configuration::Configuration {
29 : public:
30 : /** Constructor, initializes the class */
31 336 : ParticleInsertionConfiguration()
32 336 : : _insertDeleteMassEveryTimestep(1), _rSigmaCoeff(0.0), _meanPotentialEnergyFactor(0.0), _uOverlapCoeff(0.0), _stepRefCoeff(0.0), _iterMax(0),
33 336 : _restartMax(0), _tolerance(0.0), _offsetFromOuterBoundary(0.0) {}
34 :
35 : /** Destructor */
36 340 : virtual ~ParticleInsertionConfiguration() {}
37 :
38 : /** parseSubtag
39 : * @param node
40 : */
41 : void parseSubtag(tinyxml2::XMLElement* node);
42 :
43 : /** Returns name of xml tag that is associated to the configuration.
44 : * @return name of xml tag that is associated to the configuration
45 : */
46 : std::string getTag() const;
47 :
48 : /** checks if the configuration is valid. This operation usually fails, if
49 : *e.g.
50 : * 1. parseSubtag() hasn't been called, i.e. configuration has not been
51 : *used, or
52 : * 2. parseSubtag() failed due to a wrong file.
53 : * 3. If a tag ain't optional and parseSubtag() was not called (first case)
54 : * @return _isValid
55 : */
56 : bool isValid() const;
57 :
58 : /** Returns particle insertion config
59 : * @tparam LinkedCell type of the cell
60 : * @tparam dim Number of dimensions; it can be 1, 2 or 3
61 : * @param mdSolverInterface
62 : * @return particle insertion config
63 : */
64 : template <class LinkedCell, unsigned int dim>
65 : coupling::ParticleInsertion<LinkedCell, dim>*
66 4 : interpreteConfiguration(coupling::interface::MDSolverInterface<LinkedCell, dim>* const mdSolverInterface) const {
67 4 : if (_particleInsertionType == USHER) {
68 0 : return new coupling::UsherParticleInsertion<LinkedCell, dim>(_insertDeleteMassEveryTimestep, _rSigmaCoeff, _meanPotentialEnergyFactor, _uOverlapCoeff,
69 0 : _stepRefCoeff, _iterMax, _restartMax, _tolerance, _offsetFromOuterBoundary,
70 : mdSolverInterface);
71 4 : } else if (_particleInsertionType == NO_INSERTION) {
72 4 : return new coupling::NoParticleInsertion<LinkedCell, dim>();
73 : }
74 :
75 : // this case should never appear
76 : return NULL;
77 : }
78 :
79 : /** particle insertion types that are implemented.
80 : * @enum ParticleInsertionType
81 : */
82 : enum ParticleInsertionType {
83 : USHER = 0 /**< Usher*/,
84 : NO_INSERTION = 1 /**< no particle insertion */
85 : };
86 :
87 : /** Returns the particle insertion type.
88 : * @return _particleInsertionType
89 : */
90 4 : ParticleInsertionType getParticleInsertionType() const { return _particleInsertionType; }
91 :
92 : protected:
93 4 : ParticleInsertionConfiguration(unsigned int insertDeleteMassEveryTimestep, double rSigmaCoeff, double meanPotentialEnergyFactor, double uOverlapCoeff,
94 : double stepRefCoeff, unsigned int iterMax, unsigned int restartMax, double tolerance, double offsetFromOuterBoundary,
95 : ParticleInsertionType particleInsertionType)
96 4 : : _insertDeleteMassEveryTimestep(insertDeleteMassEveryTimestep), _rSigmaCoeff(rSigmaCoeff), _meanPotentialEnergyFactor(meanPotentialEnergyFactor),
97 4 : _uOverlapCoeff(uOverlapCoeff), _stepRefCoeff(stepRefCoeff), _iterMax(iterMax), _restartMax(restartMax), _tolerance(tolerance),
98 4 : _offsetFromOuterBoundary(offsetFromOuterBoundary), _particleInsertionType(particleInsertionType) {};
99 :
100 : private:
101 : static const std::string INSERT_DELETE_MASS_EVERY_TIMESTEP;
102 : static const std::string RSIGMA_COEFF;
103 : static const std::string MEAN_POTENTIAL_ENERGY_FACTOR;
104 : static const std::string UOVERLAP_COEFF;
105 : static const std::string STEPREF_COEFF;
106 : static const std::string ITER_MAX;
107 : static const std::string RESTART_MAX;
108 : static const std::string TOLERANCE;
109 : static const std::string OFFSET_FROM_OUTER_BOUNDARY;
110 :
111 : /** used to trigger mass insertion/deletion actions only every X time steps.
112 : * For NoParticleInsertion, a value of 1 is used since this is irrelevant in
113 : * this case. If the value is not specified in the configuration, a default
114 : * value of 1 is used. */
115 : unsigned int _insertDeleteMassEveryTimestep;
116 :
117 : /** r_sigma value. In the USHER paper, this value resembles the respective
118 : * parameter for choosing the stepsize when two particles overlap. In the
119 : * paper, it is stated that it should be close to unity (in sigma units; the
120 : * parameter here is also used in sigma units of the respective molecules)
121 : * and is chosen to be 0.9. If the parameter is not defined in the config,
122 : * _rSigmaCoeff is also set to 0.9.
123 : */
124 : double _rSigmaCoeff;
125 : double _meanPotentialEnergyFactor;
126 :
127 : /** overlap energy. If not defined in the config, this value is set to 10^4.
128 : * It is typically given in units of epsilon (energy parameter of the LJ
129 : * fluid).
130 : */
131 : double _uOverlapCoeff;
132 :
133 : /** coefficient determining a reference step size when stepping towards the
134 : * right energy level. From the USHER paper (Usher - An algorithm for particle
135 : * insertion in dense fluids), this coefficient is optimally chosen to be 0.1
136 : * (in sigma units; this configuration also determines this parameter in sigma
137 : * units). Thus, the parameter is set to 0.1, if it is not defined within the
138 : * configuration.
139 : */
140 : double _stepRefCoeff;
141 :
142 : /** maximum number of USHER iteration steps within one insertion cycle */
143 : unsigned int _iterMax;
144 :
145 : /** maximum number of USHER restarts, that is USHER insertion cycles */
146 : unsigned int _restartMax;
147 :
148 : /** tolerance for USHER stopping criterion. If this is not specified, we
149 : * set it to _meanPotentialEnergyFactor*2.0.
150 : */
151 : double _tolerance;
152 :
153 : /** enables valid particle positions only if the particle is at least at this
154 : * distance from an outer boundary. This is useful since open boundary forces
155 : * are not considered in the current USHER implementation. Inserting a
156 : * particle close to an outer open boundary may thus result in very strong
157 : * forces and, thus, yield instabilities.
158 : */
159 : double _offsetFromOuterBoundary;
160 :
161 : /** type of particle insertion algorithm */
162 : ParticleInsertionType _particleInsertionType;
163 : };
164 : #endif // _MOLECULARDYNAMICS_COUPLING_CONFIGURATIONS_PARTICLEINSERTIONCONFIGURATION_H_
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