1 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 Copyright (c) 2015-2021 The plumed team
3 (see the PEOPLE file at the root of the distribution for a list of names)
4
5 See http://www.plumed.org for more information.
6
7 This file is part of plumed, version 2.
8
9 plumed is free software: you can redistribute it and/or modify
10 it under the terms of the GNU Lesser General Public License as published by
11 the Free Software Foundation, either version 3 of the License, or
12 (at your option) any later version.
13
14 plumed is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU Lesser General Public License for more details.
18
19 You should have received a copy of the GNU Lesser General Public License
20 along with plumed. If not, see <http://www.gnu.org/licenses/>.
21 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
22 #ifndef __PLUMED_tools_MinimiseBase_h
23 #define __PLUMED_tools_MinimiseBase_h
24
25 #include "Minimise1DBrent.h"
26
27 namespace PLMD {
28
29 template <class FCLASS>
30 class F1dim {
31 private:
32 /// This is the pointer to the member function in the energy
33 /// calculating class that calculates the energy
34 typedef double(FCLASS::*engf_pointer)( const std::vector<double>& p, std::vector<double>& der ) const ;
35 typedef double(FCLASS::*engfnc_pointer)( const std::vector<double>& p, std::vector<double>& der ) ;
36 /// Pointer to the vector containing an initial position on the vector
37 const std::vector<double>& p;
38 /// The direction of the vector we are minimising along
39 const std::vector<double>& dir;
40 /// Tempory vector that holds a point at which we want to calculate the energy
41 std::vector<double> pt;
42 /// Vector that holds the derivatives at the point at which we calculate the energy (these are not used)
43 std::vector<double> fake_der;
44 /// Class containging the function in the class
45 FCLASS* func;
46 /// Member of class that calculates the energy we are trying to mnimise
47 engf_pointer calc;
48 /// Member of class that calcualtes the energy we are trying to minimise
49 engfnc_pointer calc2;
50 public:
51 explicit F1dim( const std::vector<double>& pp, const std::vector<double>& dd, FCLASS* ff, engf_pointer cc, engfnc_pointer cc2 );
52 /// Calculate the energy at \f$\mathbf{p} + xt*\mathbf{dir}\f$
53 double getEng( const double& xt );
54 };
55
56 template <class FCLASS>
F1dim(const std::vector<double> & pp,const std::vector<double> & dd,FCLASS * ff,engf_pointer cc,engfnc_pointer cc2)57 F1dim<FCLASS>::F1dim( const std::vector<double>& pp, const std::vector<double>& dd, FCLASS* ff, engf_pointer cc, engfnc_pointer cc2 ):
58 p(pp),
59 dir(dd),
60 pt(pp.size()),
61 fake_der(pp.size()),
62 func(ff),
63 calc(cc),
64 calc2(cc2)
65 {
66 plumed_assert( calc || calc2 );
67 }
68
69 template <class FCLASS>
getEng(const double & xt)70 double F1dim<FCLASS>::getEng( const double& xt ) {
71 for(unsigned j=0; j<pt.size(); ++j) pt[j] = p[j] + xt*dir[j];
72 if( calc ) return (func->*calc)(pt,fake_der);
73 return (func->*calc2)(pt,fake_der);
74 }
75
76 template <class FCLASS>
77 class MinimiseBase {
78 private:
79 /// This is the pointer to the member function in the energy
80 /// calculating class that calculates the energy
81 typedef double(FCLASS::*engf_pointer)( const std::vector<double>& p, std::vector<double>& der );
82 /// The class that calculates the energy given a position
83 FCLASS* myclass_func;
84 protected:
85 /// This calculates the derivatives at a point
86 double calcDerivatives( const std::vector<double>& p, std::vector<double>& der, engf_pointer myfunc );
87 public:
MinimiseBase(FCLASS * funcc)88 explicit MinimiseBase( FCLASS* funcc ) : myclass_func(funcc) {}
89 /// This is the line minimiser
90 double linemin( const std::vector<double>& dir, std::vector<double>& p, engf_pointer myfunc );
91 };
92
93 template <class FCLASS>
linemin(const std::vector<double> & dir,std::vector<double> & p,engf_pointer myfunc)94 double MinimiseBase<FCLASS>::linemin( const std::vector<double>& dir, std::vector<double>& p, engf_pointer myfunc ) {
95 // Construct the object that turns points on a line into vectors
96 F1dim<FCLASS> f1dim( p, dir, myclass_func, NULL, myfunc );
97
98 // Construct an object that will do the line search for the minimum
99 Minimise1DBrent<F1dim<FCLASS> > bb(f1dim);
100
101 // This does the actual line minimisation
102 double ax=0.0, xx=1.0;
103 bb.bracket( ax, xx, &F1dim<FCLASS>::getEng );
104 double xmin=bb.minimise( &F1dim<FCLASS>::getEng );
105 for(unsigned i=0; i<p.size(); ++i) p[i] += xmin*dir[i];
106 return bb.getMinimumValue();
107 }
108
109 template <class FCLASS>
calcDerivatives(const std::vector<double> & p,std::vector<double> & der,engf_pointer myfunc)110 double MinimiseBase<FCLASS>::calcDerivatives( const std::vector<double>& p, std::vector<double>& der, engf_pointer myfunc ) {
111 return (myclass_func->*myfunc)( p, der );
112 }
113
114 }
115 #endif
116