dft_tools/test/triqs/det_manip/det_manip1.cpp

#include <triqs/det_manip/det_manip.hpp>
#include <triqs/mc_tools/random_generator.hpp>
#include <triqs/arrays/linalg/det_and_inverse.hpp>
#include <triqs/arrays/asserts.hpp>
#include <iostream>

struct fun {

 typedef double result_type;
 typedef double argument_type;

 /*double f(double eps, double tau, double beta) const { 
   bool s = (tau>0);
   tau = (s ? tau : beta + tau); 
   return (s ? 1 : -1 ) * exp( - eps* (tau)) / (1 + exp(- beta *eps));
   }*/

 double operator()(double x, double y) const { 
  const double pi = acos(-1); 
  const double beta = 10.0; 
  const double epsi = 0.1; 
  double tau = x-y;
  bool s = (tau>0);
  tau = (s ? tau : beta + tau);
  double r = epsi + tau/beta *(1-2*epsi);
  return - 2*(pi/beta)/ std::sin ( pi *r);

  //return - 0.5*(f(0.12, x-y, beta) + f(0.43,x-y,beta) ); //+ f(-0.7,x-y,beta)); 
 }

};

template<class T1, class T2 >
void assert_close( T1 const & A, T2 const & B, double precision) {
 if ( std::abs(A-B) > precision) TRIQS_RUNTIME_ERROR<<"assert_close error : "<<A<<"\n"<<B;
}
const double PRECISION = 1.e-6;

struct test { 

 fun f;
 triqs::det_manip::det_manip<fun> D;
 double det_old,detratio;

 test() : f(), D(f,100) {}

 void check() { 
#ifndef PRINT_ALL
  std::cerr  << "det = " << D.determinant() <<  " == " << double(determinant(D.matrix()))<< std::endl;
#else
  std::cerr  << "det = " << D.determinant() <<  " == " << double(determinant(D.matrix()))<< std::endl <<
   D.inverse_matrix() << D.matrix() << triqs::arrays::matrix<double>(inverse(D.matrix()))<<  std::endl;
  std::cerr << "det_old = " << det_old << "detratio = "<< detratio<< " determin "<< D.determinant() <<std::endl;
#endif
  assert_close(D.determinant() , 1/determinant(D.inverse_matrix()), PRECISION); 
  triqs::arrays::assert_all_close( inverse(D.matrix()) , D.inverse_matrix(), PRECISION, true);
  assert_close( det_old * detratio , D.determinant(), PRECISION);
 }

 void run() { 
  triqs::mc_tools::random_generator RNG("mt19937", 23432);
  for (size_t i =0; i< 100; ++i) { 
   std::cerr<<" ------------------------------------------------"<<std::endl;
   std::cerr <<" i = "<< i << " size = "<< D.size() << std::endl; 
   // choose a move
   int mn = RNG(4);
   size_t s = D.size();
   size_t i0,j0,i1,j1;
   det_old = D.determinant();
   detratio=1;
   double x,y,x1,y1; 
   bool do_something = true;

   switch(RNG(( i>10 ? 4 : 1))) {
    case 0 :
     x = RNG(10.0), y = RNG(10.0);
     std::cerr  << " x,y = "<< x << "  "<< y << std::endl; 
     detratio = D.try_insert(RNG(s),RNG(s), x,y); 
     break;
    case 1 : 
     if (s>0) detratio = D.try_remove(RNG(s),RNG(s));
     break;
    case 2:
     std::cerr  << " Insert2" << std::endl;
     x = RNG(10.0); x1 = RNG(10.0); 
     y = RNG(10.0); y1 = RNG(10.0); 
     i0 = RNG(s); i1 = RNG(s+1);
     j0 = RNG(s); j1 = RNG(s+1);
     if ((i0 !=i1)&& (j0!=j1))  {
      detratio = D.try_insert2(i0,i1,j0,j1, x,x1,y,y1);
     }
     else do_something = false;
     break;
    case 3:
     std::cerr  << " Remove2" << std::endl;
     if (D.size()>=2) {
      i0 = RNG(s); i1 = RNG(s);
      j0 = RNG(s); j1 = RNG(s);
      if ((i0 !=i1)&& (j0!=j1))  {
       detratio = D.try_remove2(i0,i1,j0,j1);
      }
      else do_something = false;
     }
     break;
    default :
     TRIQS_RUNTIME_ERROR <<" TEST INTERNAL ERROR" ;
   };

   if (do_something) { 
    if (std::abs(detratio*det_old)> PRECISION)  {
     D.complete_operation();
     if (D.size() >0) check();
    }
    else { std::cerr  << " reject  since new det is = " << std::abs(detratio*det_old)<<std::endl;}
   }
  }
 }

};

int main(int argc, char **argv) {
 test().run();
}