Line data    Source code

       1             : /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
       2             :    Copyright (c) 2011-2023 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             : #include "Angle.h"
      23             : #include "Tools.h"
      24             : #include <cmath>
      25             : 
      26             : namespace PLMD {
      27             : 
      28           2 : double Angle::compute(const Vector& v1,const Vector& v2)const {
      29           2 :   return std::acos(dotProduct(v1,v2)/(v1.modulo()*v2.modulo()));
      30             : }
      31             : 
      32      543453 : double Angle::compute(const Vector& v1,const Vector& v2,Vector& d1,Vector& d2)const {
      33      543453 :   const double dp(dotProduct(v1,v2));
      34             :   const Vector& dp_dv1(v2);
      35             :   const Vector& dp_dv2(v1);
      36      543453 :   const double sv1(v1.modulo2());
      37      543453 :   const double sv2(v2.modulo2());
      38      543453 :   const Vector dsv1_dv1(2*v1);
      39      543453 :   const Vector dsv2_dv2(2*v2);
      40      543453 :   const double nn(1.0/std::sqrt(sv1*sv2));
      41      543453 :   const Vector dnn_dv1(-0.5*nn/sv1*dsv1_dv1);
      42      543453 :   const Vector dnn_dv2(-0.5*nn/sv2*dsv2_dv2);
      43             : 
      44      543453 :   const double dpnn(dp*nn);
      45             : 
      46      543453 :   if(dpnn>=1.0-epsilon) {
      47           1 :     d1=Vector(0.0,0.0,0.0);
      48           1 :     d2=Vector(0.0,0.0,0.0);
      49           1 :     return 0.0;
      50             :   }
      51      543452 :   if(dpnn<=-1.0+epsilon) {
      52           1 :     d1=Vector(0.0,0.0,0.0);
      53           1 :     d2=Vector(0.0,0.0,0.0);
      54           1 :     return pi;
      55             :   }
      56      543451 :   const Vector ddpnn_dv1(dp*dnn_dv1+dp_dv1*nn);
      57      543451 :   const Vector ddpnn_dv2(dp*dnn_dv2+dp_dv2*nn);
      58             : 
      59      543451 :   const double x(-1.0/std::sqrt(1-dpnn*dpnn));
      60             : 
      61      543451 :   d1=x*ddpnn_dv1;
      62      543451 :   d2=x*ddpnn_dv2;
      63             : 
      64             : 
      65      543451 :   return std::acos(dpnn);
      66             : }
      67             : 
      68             : }