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dft_tools/doc/tutorials/det_manip_tutorial_6.cpp
tayral edd1ff4529 Restructuring documentation.
A first general restructuration of the doc according to the pattern [tour|tutorial|reference].
In the reference part, objects are documented per topic.
In each topic, [definition|c++|python|hdf5] (not yet implemented)
2014-10-18 12:21:08 +01:00

24 lines
1.1 KiB
C++

#include <triqs/det_manip/det_manip.hpp>
struct fun {
typedef double result_type;
typedef double argument_type;
double operator()(double x, double y) const { return (exp(x) - y * y); }
};
int main() {
triqs::det_manip::det_manip<fun> D(fun(), std::vector<double>{1, 2, 2.5}, std::vector<double>{3, 4, 9});
std::cout << std::endl << "After construction, D.matrix()=" << D.matrix() << std::endl << std::endl;
int i0 = 2, i1 = 1, j0 = 0, j1 = 1; // number of the removed lines and columns
std::cout << "We want to remove 2 lines and 2 columns for i0=" << i0 << ", j0=" << j0 << ", i1=" << i1 << ", j1=" << j1 << "."
<< std::endl;
// (try of) removal of a line and a column at position (1,0) in the matrix.
double detratio = D.try_remove2(i0, i1, j0, j1); // the ratio between new and old determinants
// while the operation is not complete, the matrix stays unchanged
std::cout << "After try_remove2, D.matrix()=" << D.matrix() << std::endl;
// here we validate the removal: the (inverse) matrix and determinant are updated
D.complete_operation();
std::cout << "After complete_operation, D.matrix()=" << D.matrix() << std::endl << std::endl;
}