Line data    Source code

       1             : /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
       2             :    Copyright (c) 2016-2021 The VES code team
       3             :    (see the PEOPLE-VES file at the root of this folder for a list of names)
       4             : 
       5             :    See http://www.ves-code.org for more information.
       6             : 
       7             :    This file is part of VES code module.
       8             : 
       9             :    The VES code module 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             :    The VES code module 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 the VES code module.  If not, see <http://www.gnu.org/licenses/>.
      21             : +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
      22             : 
      23             : #include "BasisFunctions.h"
      24             : 
      25             : #include "core/ActionRegister.h"
      26             : 
      27             : 
      28             : namespace PLMD {
      29             : namespace ves {
      30             : 
      31             : //+PLUMEDOC VES_BASISF BF_POWERS
      32             : /*
      33             : Polynomial power basis functions.
      34             : 
      35             : !!! attention ""
      36             : 
      37             :     __These basis functions should not be used in conventional biasing simulations__.
      38             :     Instead you should use orthogonal basis functions like Legendre or
      39             :     Chebyshev polynomials. They are only included for usage in [ves_md_linearexpansion](ves_md_linearexpansion.md)
      40             :     and some special cases.
      41             : 
      42             : Basis functions given by polynomial powers defined on a bounded interval.
      43             : You need to provide the interval $[a,b]$
      44             : on which the basis functions are to be used, and the order of the
      45             : expansion $N$ (i.e. the highest power used).
      46             : The total number of basis functions is $N+1$ as the constant $f_{0}(x)=1$
      47             : is also included.
      48             : These basis functions should not be used for periodic CVs.
      49             : 
      50             : The basis functions are given by
      51             : 
      52             : $$
      53             : \begin{aligned}
      54             : f_{0}(x)    &= 1 \\
      55             : f_{1}(x)    &= x \\
      56             : f_{2}(x)    &= x^2 \\
      57             : & \vdots \\
      58             : f_{n}(x)    &= x^n \\
      59             : & \vdots \\
      60             : f_{N}(x)    &= x^N \\
      61             : \end{aligned}
      62             : $$
      63             : 
      64             : Note that these basis functions are __not__ orthogonal. In fact the integral
      65             : over the uniform target distribution blows up as the interval is increased.
      66             : Therefore they should not be used in conventional biasing simulations.
      67             : However, they can be useful for usage with [ves_md_linearexpansion](ves_md_linearexpansion.md).
      68             : 
      69             : ## Examples
      70             : 
      71             : Here we employ a polynomial power expansion of order 5
      72             : over the interval -2.0 to 2.0.
      73             : This results in a total number of 6 basis functions.
      74             : The label used to identify  the basis function action can then be
      75             : referenced later on in the input file.
      76             : 
      77             : ```plumed
      78             : BF_POWERS MINIMUM=-2.0 MAXIMUM=2.0 ORDER=5 LABEL=bf_pow
      79             : ```
      80             : 
      81             : 
      82             : */
      83             : //+ENDPLUMEDOC
      84             : 
      85             : class BF_Powers : public BasisFunctions {
      86             :   double inv_normfactor_;
      87             :   void setupLabels() override;
      88             : public:
      89             :   static void registerKeywords( Keywords&);
      90             :   explicit BF_Powers(const ActionOptions&);
      91             :   void getAllValues(const double, double&, bool&, std::vector<double>&, std::vector<double>&) const override;
      92             : };
      93             : 
      94             : 
      95             : PLUMED_REGISTER_ACTION(BF_Powers,"BF_POWERS")
      96             : 
      97             : 
      98          18 : void BF_Powers::registerKeywords(Keywords& keys) {
      99          18 :   BasisFunctions::registerKeywords(keys);
     100          18 :   keys.add("optional","NORMALIZATION","The normalization factor that is used to normalize the basis functions. By default it is 1.0.");
     101          18 :   keys.remove("NUMERICAL_INTEGRALS");
     102          18 : }
     103             : 
     104          16 : BF_Powers::BF_Powers(const ActionOptions&ao):
     105          16 :   PLUMED_VES_BASISFUNCTIONS_INIT(ao) {
     106          16 :   setNumberOfBasisFunctions(getOrder()+1);
     107          16 :   setIntrinsicInterval(intervalMin(),intervalMax());
     108          16 :   double normfactor_=1.0;
     109          16 :   parse("NORMALIZATION",normfactor_);
     110          16 :   if(normfactor_!=1.0) {
     111           0 :     addKeywordToList("NORMALIZATION",normfactor_);
     112             :   }
     113          16 :   inv_normfactor_=1.0/normfactor_;
     114             :   setNonPeriodic();
     115             :   setIntervalBounded();
     116          16 :   setType("polynom_powers");
     117          16 :   setDescription("Polynomial Powers");
     118          16 :   setupBF();
     119          16 :   log.printf("   normalization factor: %f\n",normfactor_);
     120          16 :   checkRead();
     121          16 : }
     122             : 
     123             : 
     124      842119 : void BF_Powers::getAllValues(const double arg, double& argT, bool& inside_range, std::vector<double>& values, std::vector<double>& derivs) const {
     125      842119 :   inside_range=true;
     126      842119 :   argT=checkIfArgumentInsideInterval(arg,inside_range);
     127             :   //
     128      842119 :   values[0]=1.0;
     129      842119 :   derivs[0]=0.0;
     130             :   //
     131     4210595 :   for(unsigned int i=1; i < getNumberOfBasisFunctions(); i++) {
     132             :     // double io = static_cast<double>(i);
     133             :     // values[i] = pow(argT,io);
     134             :     // derivs[i] = io*pow(argT,io-1.0);
     135     3368476 :     values[i] = argT*values[i-1];
     136     3368476 :     derivs[i]=values[i-1]+argT*derivs[i-1];
     137             :   }
     138      842119 :   if(!inside_range) {
     139         480 :     for(unsigned int i=0; i<derivs.size(); i++) {
     140         400 :       derivs[i]=0.0;
     141             :     }
     142             :   }
     143      842119 : }
     144             : 
     145             : 
     146          16 : void BF_Powers::setupLabels() {
     147          16 :   setLabel(0,"1");
     148          80 :   for(unsigned int i=1; i < getOrder()+1; i++) {
     149             :     std::string is;
     150          64 :     Tools::convert(i,is);
     151         128 :     setLabel(i,"s^"+is);
     152             :   }
     153          16 : }
     154             : 
     155             : }
     156             : }