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