Contents

• NAME
• SYNOPSIS
  • F95 INTERFACE
  • C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

     ssytrs - solve a system of linear equations A*X = B  with  a
     real symmetric matrix A using the factorization A = U*D*U**T
     or A = L*D*L**T computed by SSYTRF

SYNOPSIS

     SUBROUTINE SSYTRS(UPLO, N, NRHS, A, LDA, IPIVOT, B, LDB, INFO)

     CHARACTER * 1 UPLO
     INTEGER N, NRHS, LDA, LDB, INFO
     INTEGER IPIVOT(*)
     REAL A(LDA,*), B(LDB,*)

     SUBROUTINE SSYTRS_64(UPLO, N, NRHS, A, LDA, IPIVOT, B, LDB, INFO)

     CHARACTER * 1 UPLO
     INTEGER*8 N, NRHS, LDA, LDB, INFO
     INTEGER*8 IPIVOT(*)
     REAL A(LDA,*), B(LDB,*)

  F95 INTERFACE
     SUBROUTINE SYTRS(UPLO, N, NRHS, A, [LDA], IPIVOT, B, [LDB], [INFO])

     CHARACTER(LEN=1) :: UPLO
     INTEGER :: N, NRHS, LDA, LDB, INFO
     INTEGER, DIMENSION(:) :: IPIVOT
     REAL, DIMENSION(:,:) :: A, B

     SUBROUTINE SYTRS_64(UPLO, N, NRHS, A, [LDA], IPIVOT, B, [LDB], [INFO])

     CHARACTER(LEN=1) :: UPLO
     INTEGER(8) :: N, NRHS, LDA, LDB, INFO
     INTEGER(8), DIMENSION(:) :: IPIVOT
     REAL, DIMENSION(:,:) :: A, B

  C INTERFACE
     #include <sunperf.h>

     void ssytrs(char uplo, int n, int nrhs, float *a,  int  lda,
               int *ipivot, float *b, int ldb, int *info);

     void ssytrs_64(char uplo, long n, long nrhs, float *a,  long
               lda,  long  *ipivot,  float  *b,  long  ldb,  long
               *info);

PURPOSE

     ssytrs solves a system of linear equations A*X =  B  with  a
     real symmetric matrix A using the factorization A = U*D*U**T
     or A = L*D*L**T computed by SSYTRF.

ARGUMENTS

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

     NRHS (input)
               The number of right hand sides, i.e.,  the  number
               of columns of the matrix B.  NRHS >= 0.

     A (input) The block diagonal matrix D  and  the  multipliers
               used  to  obtain  the factor U or L as computed by
               SSYTRF.

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

     IPIVOT (input)
               Details of the interchanges and the  block  struc-
               ture of D as determined by SSYTRF.

     B (input/output)
               On entry, the right hand side matrix B.  On  exit,
               the solution matrix X.

     LDB (input)
               The leading dimension of  the  array  B.   LDB  >=
               max(1,N).

     INFO (output)
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille-
               gal value