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16 lines
590 B
C++
16 lines
590 B
C++
#include <iostream>
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#include <Eigen/SVD>
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float inv_cond(const Eigen::Ref<const Eigen::MatrixXf>& a) {
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const Eigen::VectorXf sing_vals = a.jacobiSvd().singularValues();
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return sing_vals(sing_vals.size() - 1) / sing_vals(0);
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}
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int main() {
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Eigen::MatrixXf m = Eigen::MatrixXf::Random(4, 4);
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std::cout << "matrix m:\n" << m << "\n\n";
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std::cout << "inv_cond(m): " << inv_cond(m) << "\n";
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std::cout << "inv_cond(m(1:3,1:3)): " << inv_cond(m.topLeftCorner(3, 3)) << "\n";
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std::cout << "inv_cond(m+I): " << inv_cond(m + Eigen::MatrixXf::Identity(4, 4)) << "\n";
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}
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