dstev.f man page

dstev.f —

Synopsis

Functions/Subroutines

subroutine dstev (JOBZ, N, D, E, Z, LDZ, WORK, INFO)
DSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices

Function/Subroutine Documentation

subroutine dstev (characterJOBZ, integerN, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension( ldz, * )Z, integerLDZ, double precision, dimension( * )WORK, integerINFO)

DSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices

Purpose:

DSTEV computes all eigenvalues and, optionally, eigenvectors of a
real symmetric tridiagonal matrix A.

Parameters:

JOBZ

JOBZ is CHARACTER*1
= 'N':  Compute eigenvalues only;
= 'V':  Compute eigenvalues and eigenvectors.

N

N is INTEGER
The order of the matrix.  N >= 0.

D

D is DOUBLE PRECISION array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix
A.
On exit, if INFO = 0, the eigenvalues in ascending order.

E

E is DOUBLE PRECISION array, dimension (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A, stored in elements 1 to N-1 of E.
On exit, the contents of E are destroyed.

Z

Z is DOUBLE PRECISION array, dimension (LDZ, N)
If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal
eigenvectors of the matrix A, with the i-th column of Z
holding the eigenvector associated with D(i).
If JOBZ = 'N', then Z is not referenced.

LDZ

LDZ is INTEGER
The leading dimension of the array Z.  LDZ >= 1, and if
JOBZ = 'V', LDZ >= max(1,N).

WORK

WORK is DOUBLE PRECISION array, dimension (max(1,2*N-2))
If JOBZ = 'N', WORK is not referenced.

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
> 0:  if INFO = i, the algorithm failed to converge; i
      off-diagonal elements of E did not converge to zero.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 117 of file dstev.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dstev(3) is an alias of dstev.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK