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NAME
     ssttrf - compute the factorization of a symmetric  tridiago-
     nal matrix A

SYNOPSIS
     SUBROUTINE SSTTRF( N, L, D, SUBL, IPIV, INFO )

     INTEGER INFO, N

     REAL D( * )

     REAL L( * ), SUBL( * )



     #include <sunperf.h>

     void ssttrf(int n, float *l,  float  *d,  float  *subl,  int
               *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 tri-
               diagonal  matrix A.  On exit, part of the factori-
               zation of A.

     D         (input/output) REAL array, dimension (N)
               On entry, the n diagonal elements of the tridiago-
               nal matrix A.  On exit, the n diagonal elements of
               the diagonal matrix D from the L*D*L**H factoriza-
               tion 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
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille-
               gal value
               > 0:  if INFO = i, D(k,k) is  exactly  zero.   The
               factorization  has  been  completed, but the block
               diagonal matrix D is exactly singular and division
               by zero will occur if it is used to solve a system
               of equations.

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