Singular value decomposition: Difference between revisions

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 |-0.7071067812 -0.7071067812|
 |-0.7071067812  0.7071067812|
+</pre>
+=={{header|C++}}==
+{{trans|C}}
+{{libheader|GNU Scientific Library}}
+Requires C++11 or higher.
+<syntaxhighlight lang="C++">
+#include <iostream>
+#include <iomanip>
+#include <gsl/gsl_linalg.h>
+void gsl_matrix_print(const gsl_matrix *M) {
+	auto rows = M->size1;
+	auto cols = M->size2;
+	std::cout.precision(10);
+	std::cout.setf(std::ios::fixed);
+	for (auto i = 0; i < rows; i++) {
+		std::cout << "|";
+		for (auto j = 0; j < cols; j++) {
+			std::cout << gsl_matrix_get(M, i, j) << "  ";
+		}
+		std::cout << "|" << std::endl;
+	}
+	std::cout << std::endl;
+}
+int main(int argc, char** argv) {
+	double a[] = {3, 0, 4, 5};
+	auto A = gsl_matrix_view_array(a, 2, 2);
+	auto *V = gsl_matrix_alloc(2, 2);
+	auto *S = gsl_vector_alloc(2);
+	auto *work = gsl_vector_alloc(2);
+	gsl_linalg_SV_decomp(&A.matrix, V, S, work);
+	double s[] = {S->data[0], 0.0, 0.0, S->data[1]};
+	auto SM = gsl_matrix_view_array(s, 2, 2);
+	std::cout << "U:" << std::endl;
+	gsl_matrix_print(&A.matrix);
+	std::cout << "Sigma:" << std::endl;
+    gsl_matrix_print(&SM.matrix);
+	std::cout << "V:" << std::endl;
+    gsl_matrix_print(V);
+	gsl_matrix_free(V);
+	gsl_vector_free(S);
+	gsl_vector_free(work);
+	return 0;
+}
+</syntaxhighlight>
+{{out}}
+<pre>
+U:
+|-0.3162277660  -0.9486832981  |
+|-0.9486832981  0.3162277660  |
+Sigma:
+|6.7082039325  0.0000000000  |
+|0.0000000000  2.2360679775  |
+V:
+|-0.7071067812  -0.7071067812  |
+|-0.7071067812  0.7071067812  |
 </pre>