spttrs(3F)

NAME
     SPTTRS - solve a system of linear equations A * X = B with a symmetric
     positive definite tridiagonal matrix A using the factorization A =
     L*D*L**T or A = U**T*D*U computed by SPTTRF

SYNOPSIS
     SUBROUTINE SPTTRS( N, NRHS, D, E, B, LDB, INFO )

         INTEGER        INFO, LDB, N, NRHS

         REAL           B( LDB, * ), D( * ), E( * )

PURPOSE
     SPTTRS solves a system of linear equations A * X = B with a symmetric
     positive definite tridiagonal matrix A using the factorization A =
     L*D*L**T or A = U**T*D*U computed by SPTTRF.  (The two forms are
     equivalent if A is real.)


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

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

     D       (input) REAL array, dimension (N)
             The n diagonal elements of the diagonal matrix D from the
             factorization computed by SPTTRF.

     E       (input) REAL array, dimension (N-1)
             The (n-1) off-diagonal elements of the unit bidiagonal factor U
             or L from the factorization computed by SPTTRF.

     B       (input/output) REAL array, dimension (LDB,NRHS)
             On entry, the right hand side matrix B.  On exit, the solution
             matrix X.

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

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