Contents

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

NAME

     SSPTRS - solve a system of linear equations A*X = B  with  a
     real  symmetric  matrix  A stored in packed format using the
     factorization A = U*D*U**T  or  A  =  L*D*L**T  computed  by
     SSPTRF

SYNOPSIS

     SUBROUTINE SSPTRS(UPLO, N, NRHS, AP, IPIVOT, B, LDB, INFO)

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

     SUBROUTINE SSPTRS_64(UPLO, N, NRHS, AP, IPIVOT, B, LDB, INFO)

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

  F95 INTERFACE
     SUBROUTINE SPTRS(UPLO, N, [NRHS], AP, IPIVOT, B, [LDB], [INFO])

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

     SUBROUTINE SPTRS_64(UPLO, N, [NRHS], AP, IPIVOT, B, [LDB], [INFO])

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

  C INTERFACE
     #include <sunperf.h>

     void ssptrs(char uplo, int  n,  int  nrhs,  float  *ap,  int
               *ipivot, float *b, int ldb, int *info);

     void ssptrs_64(char uplo, long n, long nrhs, float *ap, long
               *ipivot, float *b, long ldb, long *info);

PURPOSE

     ssptrs solves a system of linear equations A*X =  B  with  a
     real  symmetric  matrix  A stored in packed format using the
     factorization A = U*D*U**T  or  A  =  L*D*L**T  computed  by
     SSPTRF.

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.

     AP (input)
               Real array, dimension (N*(N+1)/2) The block diago-
               nal  matrix  D  and the multipliers used to obtain
               the factor U or L as computed by SSPTRF, stored as
               a packed triangular matrix.

     IPIVOT (input)
               Integer array, dimension (N) Details of the inter-
               changes and the block structure of D as determined
               by SSPTRF.

     B (input/output)
               Real array, dimension (LDB, NRHS)  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