ssttrf

NAME

ssttrf - compute the factorization of a symmetric tridiagonal matrix A

SYNOPSIS

  SUBROUTINE SSTTRF( N, L, D, SUBL, IPIV, INFO)
  INTEGER N, INFO
  INTEGER IPIV(*)
  REAL L(*), D(*), SUBL(*)
 
  SUBROUTINE SSTTRF_64( N, L, D, SUBL, IPIV, INFO)
  INTEGER*8 N, INFO
  INTEGER*8 IPIV(*)
  REAL L(*), D(*), SUBL(*)

F95 INTERFACE

  SUBROUTINE STTRF( [N], L, D, SUBL, IPIV, [INFO])
  INTEGER :: N, INFO
  INTEGER, DIMENSION(:) :: IPIV
  REAL, DIMENSION(:) :: L, D, SUBL
 
  SUBROUTINE STTRF_64( [N], L, D, SUBL, IPIV, [INFO])
  INTEGER(8) :: N, INFO
  INTEGER(8), DIMENSION(:) :: IPIV
  REAL, DIMENSION(:) :: L, D, SUBL

C INTERFACE

#include <sunperf.h>

void ssttrf(int n, float *l, float *d, float *subl, int *ipiv, int *info);

void ssttrf_64(long n, float *l, float *d, float *subl, long *ipiv, long *info);

PURPOSE

ssttrf computes the factorization of a complex Hermitian tridiagonal matrix A.

ARGUMENTS

* N (input)

 INTEGER

The order of the matrix A. N >= 0.

* L (input/output)

 REAL array, dimension (N)

On entry, the n-1 subdiagonal elements of the tridiagonal matrix A. On exit, part of the factorization of A.

* D (input/output)

 REAL array, dimension (N)

On entry, the n diagonal elements of the tridiagonal matrix A. On exit, the n diagonal elements of the diagonal matrix D from the L*D*L**H factorization of A.

* SUBL (output)

 REAL array, dimension (N)

On exit, part of the factorization of A.

* IPIV (output)

 INTEGER array, dimension (N)

On exit, the pivot indices of the factorization.

* INFO (output)

 INTEGER