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Please note that the recommended version of Scilab is 6.0.2. This page might be outdated.
See the recommended documentation of this function

Scilab manual >> Linear Algebra > hess

hess

Hessenberg form

Calling Sequence

H = hess(A)
[U,H] = hess(A)

Arguments

A

real or complex square matrix

H

real or complex square matrix

U

orthogonal or unitary square matrix

Description

[U,H] = hess(A) produces a unitary matrix U and a Hessenberg matrix H so that A = U*H*U' and U'*U = Identity. By itself, hess(A) returns H.

The Hessenberg form of a matrix is zero below the first subdiagonal. If the matrix is symmetric or Hermitian, the form is tridiagonal.

References

hess function is based on the Lapack routines DGEHRD, DORGHR for real matrices and ZGEHRD, ZORGHR for the complex case.

Examples

A=rand(3,3);[U,H]=hess(A);
and( abs(U*H*U'-A)<1.d-10 )

See Also

Used Functions

hess function is based on the Lapack routines DGEHRD, DORGHR for real matrices and ZGEHRD, ZORGHR for the complex case.

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Last updated:
Wed Jan 26 16:23:41 CET 2011