dsterf(3P) Sun Performance Library dsterf(3P)NAMEdsterf - compute all eigenvalues of a symmetric tridiagonal matrix
using the Pal-Walker-Kahan variant of the QL or QR algorithm
SYNOPSIS
SUBROUTINE DSTERF(N, D, E, INFO)
INTEGER N, INFO
DOUBLE PRECISION D(*), E(*)
SUBROUTINE DSTERF_64(N, D, E, INFO)
INTEGER*8 N, INFO
DOUBLE PRECISION D(*), E(*)
F95 INTERFACE
SUBROUTINE STERF([N], D, E, [INFO])
INTEGER :: N, INFO
REAL(8), DIMENSION(:) :: D, E
SUBROUTINE STERF_64([N], D, E, [INFO])
INTEGER(8) :: N, INFO
REAL(8), DIMENSION(:) :: D, E
C INTERFACE
#include <sunperf.h>
void dsterf(int n, double *d, double *e, int *info);
void dsterf_64(long n, double *d, double *e, long *info);
PURPOSEdsterf computes all eigenvalues of a symmetric tridiagonal matrix using
the Pal-Walker-Kahan variant of the QL or QR algorithm.
ARGUMENTS
N (input) The order of the matrix. N >= 0.
D (input/output)
On entry, the n diagonal elements of the tridiagonal matrix.
On exit, if INFO = 0, the eigenvalues in ascending order.
E (input/output)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix. On exit, E has been destroyed.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: the algorithm failed to find all of the eigenvalues in
a total of 30*N iterations; if INFO = i, then i elements of E
have not converged to zero.
6 Mar 2009 dsterf(3P)
