SSTEV (3)  Linux Manuals
NAME
sstev.f 
SYNOPSIS
Functions/Subroutines
subroutine sstev (JOBZ, N, D, E, Z, LDZ, WORK, INFO)
SSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices
Function/Subroutine Documentation
subroutine sstev (characterJOBZ, integerN, real, dimension( * )D, real, dimension( * )E, real, dimension( ldz, * )Z, integerLDZ, real, dimension( * )WORK, integerINFO)
SSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices
Purpose:

SSTEV 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.
NN is INTEGER The order of the matrix. N >= 0.
DD is REAL array, dimension (N) On entry, the n diagonal elements of the tridiagonal matrix A. On exit, if INFO = 0, the eigenvalues in ascending order.
EE is REAL array, dimension (N1) On entry, the (n1) subdiagonal elements of the tridiagonal matrix A, stored in elements 1 to N1 of E. On exit, the contents of E are destroyed.
ZZ is REAL array, dimension (LDZ, N) If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal eigenvectors of the matrix A, with the ith column of Z holding the eigenvector associated with D(i). If JOBZ = 'N', then Z is not referenced.
LDZLDZ is INTEGER The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N).
WORKWORK is REAL array, dimension (max(1,2*N2)) If JOBZ = 'N', WORK is not referenced.
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, the algorithm failed to converge; i offdiagonal 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 sstev.f.
Author
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