eigenvaluesHessenbergCompute eigenvalues of an upper Hessenberg form matrix |
This information is part of the Modelica Standard Library maintained by the Modelica Association.
ev = Matrices.Utilities.eigenvaluesHessenberg(H); (ev, info) = Matrices.Utilities.eigenvaluesHessenberg(H);
This function computes the eigenvalues of a Hessenberg form matrix. Transformation to Hessenberg form is the first step in eigenvalue computation for arbitrary matrices with QR decomposition. This step can be skipped if the matrix has already Hessenberg form.
The function uses the LAPACK-routine dhseqr. Output info
is 0 for a successful call of this
function.
See Matrices.LAPACK.dhseqr for details
Real A[3,3] = [1,2,3; 9,8,7; 0,1,0]; Real ev[3,2]; ev := Matrices.Utilities.eigenvaluesHessenberg(A); // ev = [10.7538, 0.0; -0.8769, 1.0444; -0.8769, -1.0444] // = {10.7538, -0.8769 +- i*1.0444}
H |
Type: Real[:,size(H, 1)] Description: Hessenberg matrix H |
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ev |
Type: Real[size(H, 1),2] Description: Eigenvalues |
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info |
Default Value: 0 Type: Integer |