1 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 Copyright (c) 2016-2021 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_RootFindingBase_h
23 #define __PLUMED_tools_RootFindingBase_h
24
25 #include "MinimiseBase.h"
26 #include "Brent1DRootSearch.h"
27
28 namespace PLMD {
29
30 template <class FCLASS>
31 class RootFindingBase {
32 private:
33 /// This is the pointer to the member function in the energy
34 /// calculating class that calculates the energy
35 typedef double(FCLASS::*engf_pointer)( const std::vector<double>& p, std::vector<double>& der ) const ;
36 typedef double(FCLASS::*engfnc_pointer)( const std::vector<double>& p, std::vector<double>& der ) ;
37 /// The class that calculates the energy given a position
38 FCLASS* myclass_func;
39 /// This actually does the search for a root
40 void doSearch( const std::vector<double>& dir, std::vector<double>& p, F1dim<FCLASS>& f1dim ) const ;
41 public:
RootFindingBase(FCLASS * funcc)42 explicit RootFindingBase( FCLASS* funcc ) : myclass_func(funcc) {}
43 /// This is the line minimiser
44 void linesearch( const std::vector<double>& dir, std::vector<double>& p, engf_pointer myfunc ) const ;
45 void lsearch( const std::vector<double>& dir, std::vector<double>& p, engfnc_pointer myfunc ) const ;
46 };
47
48 template <class FCLASS>
doSearch(const std::vector<double> & dir,std::vector<double> & p,F1dim<FCLASS> & f1dim)49 void RootFindingBase<FCLASS>::doSearch( const std::vector<double>& dir, std::vector<double>& p, F1dim<FCLASS>& f1dim ) const {
50 // Construct an object that will do the line search for the minimum
51 Brent1DRootSearch<F1dim<FCLASS> > bb(f1dim);
52
53 // This does the actual search for the root
54 double ax=0.0, xx=1.0;
55 bb.bracket( ax, xx, &F1dim<FCLASS>::getEng );
56 double xmin=bb.search( &F1dim<FCLASS>::getEng );
57 for(unsigned i=0; i<p.size(); ++i) p[i] += xmin*dir[i];
58 }
59
60 template <class FCLASS>
linesearch(const std::vector<double> & dir,std::vector<double> & p,engf_pointer myfunc)61 void RootFindingBase<FCLASS>::linesearch( const std::vector<double>& dir, std::vector<double>& p, engf_pointer myfunc ) const {
62 // Construct the object that turns points on a line into vectors
63 F1dim<FCLASS> f1dim( p, dir, myclass_func, myfunc, NULL );
64 // Actually do the search
65 doSearch( dir, p, f1dim );
66 }
67
68 template <class FCLASS>
lsearch(const std::vector<double> & dir,std::vector<double> & p,engfnc_pointer myfunc)69 void RootFindingBase<FCLASS>::lsearch( const std::vector<double>& dir, std::vector<double>& p, engfnc_pointer myfunc ) const {
70 // Construct the object that turns points on a line into vectors
71 F1dim<FCLASS> f1dim( p, dir, myclass_func, NULL, myfunc );
72 // Actually do the search
73 doSearch( dir, p, f1dim );
74 }
75
76 }
77 #endif
78