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NAME
     ssytri - compute the inverse of a real symmetric  indefinite
     matrix  A  using  the  factorization  A  =  U*D*U**T  or A =
     L*D*L**T computed by SSYTRF

SYNOPSIS
     SUBROUTINE SSYTRI( UPLO, N, A, LDA, IPIV, WORK, INFO )

     CHARACTER UPLO

     INTEGER INFO, LDA, N

     INTEGER IPIV( * )

     REAL A( LDA, * ), WORK( * )



     #include <sunperf.h>

     void ssytri(char uplo,  int  n,  float  *sa,  int  lda,  int
               *ipivot, int *info) ;

PURPOSE
     SSYTRI computes the inverse of a real  symmetric  indefinite
     matrix  A  using  the  factorization  A  =  U*D*U**T  or A =
     L*D*L**T computed by SSYTRF.


ARGUMENTS
     UPLO      (input) CHARACTER*1
               Specifies whether the details of the factorization
               are stored as an upper or lower triangular matrix.
               = 'U':  Upper triangular, form is A = U*D*U**T;
               = 'L':  Lower triangular, form is A = L*D*L**T.

     N         (input) INTEGER
               The order of the matrix A.  N >= 0.

     A         (input/output) REAL array, dimension (LDA,N)
               On entry, the block diagonal matrix D and the mul-
               tipliers  used to obtain the factor U or L as com-
               puted by SSYTRF.

               On exit, if INFO = 0, the (symmetric)  inverse  of
               the  original  matrix.   If  UPLO = 'U', the upper
               triangular part of the inverse is formed  and  the
               part of A below the diagonal is not referenced; if
               UPLO =  'L'  the  lower  triangular  part  of  the
               inverse  is  formed  and  the  part of A above the
               diagonal is not referenced.

     LDA       (input) INTEGER
               The leading dimension of  the  array  A.   LDA  >=
               max(1,N).

     IPIV      (input) INTEGER array, dimension (N)
               Details of the interchanges and the  block  struc-
               ture of D as determined by SSYTRF.

     WORK      (workspace) REAL array, dimension (N)

     INFO      (output) INTEGER
               = 0: successful exit
               < 0: if INFO = -i, the i-th argument had an  ille-
               gal value
               > 0: if INFO = i, D(i,i) = 0; the matrix is singu-
               lar and its inverse could not be computed.

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