Scilab Home page | Wiki | Bug tracker | Forge | Mailing list archives | ATOMS | File exchange
Please login or create an account
Change language to: English - Français - Português - 日本語

Please note that the recommended version of Scilab is 6.0.0. This page might be outdated.
See the recommended documentation of this function

Справка Scilab >> Linear Algebra > Eigenvalue and Singular Value > 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

  • qr — QR decomposition
  • contr — controllability, controllable subspace, staircase
  • schur — [ordered] Schur decomposition of matrix and pencils

Used Functions

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

Scilab Enterprises
Copyright (c) 2011-2017 (Scilab Enterprises)
Copyright (c) 1989-2012 (INRIA)
Copyright (c) 1989-2007 (ENPC)
with contributors
Last updated:
Thu Oct 02 14:01:04 CEST 2014