1 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2    Copyright (c) 2012-2021 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_LatticeReduction_h
23 #define __PLUMED_tools_LatticeReduction_h
24 
25 #include "Vector.h"
26 #include "Tensor.h"
27 
28 namespace PLMD {
29 
30 /**
31 Class implementing algorithms for lattice reduction.
32 
33 This class implements algorithms described in
34 Igor Semaev, A 3-Dimensional Lattice Reduction Algorithm, CaLC 2001, LNCS 2146, pp. 181–193, 2001.
35 It just collect static methods in a separate namespace.
36 */
37 class LatticeReduction {
38 /// Gaussian reduction
39   static void reduce(Vector&a,Vector&b);
40 /// Obtain three reduce-2 vectors (Algorithm 1 in the paper), equivalent to reduce2(Tensor&t)
41   static void reduce2(Vector&a,Vector&b,Vector&c);
42 /// Check if two vectors are reduced
43   static bool isReduced(const Vector&a,const Vector&b);
44 /// Check if three vectors are reduced
45   static bool isReduced(const Vector&a,const Vector&b,const Vector &c);
46 /// Check if three vectors are reduced-2
47   static bool isReduced2(const Vector&a,const Vector&b,const Vector &c);
48 /// Obtain three reduce-2 vectors (Algorithm 1 in the paper), equivalent to reduce2(Vector&a,Vector&b,Vector&c)
49   static void reduce2(Tensor&t);
50 /// Sort three vectors by modulo
51   static void sort(Vector v[3]);
52 public:
53 /// Reduce a basis in place, maps to reduceFast()
54   static void reduce(Tensor&t);
55 /// Reduce a basis in place using the slow algorithm (Algorithm 2 in the paper)
56   static void reduceSlow(Tensor&t);
57 /// Reduce a basis in place using the fast algorithm (Algorithm 3 in the paper)
58   static void reduceFast(Tensor&t);
59 /// Check if a basis is reduced
60   static bool isReduced(const Tensor&t);
61 };
62 
63 }
64 
65 #endif
66 
67