Files
eigen/doc/snippets/Tridiagonalization_decomposeInPlace.cpp
2026-05-04 00:36:12 +00:00

16 lines
667 B
C++

// SPDX-FileCopyrightText: The Eigen Authors
// SPDX-License-Identifier: MPL-2.0
MatrixXd X = MatrixXd::Random(5, 5);
MatrixXd A = X + X.transpose();
cout << "Here is a random symmetric 5x5 matrix:" << endl << A << endl << endl;
VectorXd diag(5);
VectorXd subdiag(4);
VectorXd hcoeffs(4); // Scratch space for householder reflector.
VectorXd workspace(5);
internal::tridiagonalization_inplace(A, diag, subdiag, hcoeffs, workspace, true);
cout << "The orthogonal matrix Q is:" << endl << A << endl;
cout << "The diagonal of the tridiagonal matrix T is:" << endl << diag << endl;
cout << "The subdiagonal of the tridiagonal matrix T is:" << endl << subdiag << endl;