DPTSV(3)
computes the solution to a real system of linear equations A*X = B, where A is an NbyN symmetric positive definite tridiagonal matrix, and X and B are NbyNRHS matrices
SYNOPSIS
 SUBROUTINE DPTSV(

N, NRHS, D, E, B, LDB, INFO )

INTEGER
INFO, LDB, N, NRHS

DOUBLE
PRECISION B( LDB, * ), D( * ), E( * )
PURPOSE
DPTSV computes the solution to a real system of linear equations
A*X = B, where A is an NbyN symmetric positive definite tridiagonal
matrix, and X and B are NbyNRHS matrices.
A is factored as A = L*D*L**T, and the factored form of A is then
used to solve the system of equations.
ARGUMENTS
 N (input) INTEGER

The order of the 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/output) DOUBLE PRECISION array, dimension (N)

On entry, the n diagonal elements of the tridiagonal matrix
A. On exit, the n diagonal elements of the diagonal matrix
D from the factorization A = L*D*L**T.
 E (input/output) DOUBLE PRECISION array, dimension (N1)

On entry, the (n1) subdiagonal elements of the tridiagonal
matrix A. On exit, the (n1) subdiagonal elements of the
unit bidiagonal factor L from the L*D*L**T factorization of
A. (E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the U**T*D*U factorization of A.)
 B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)

On entry, the NbyNRHS right hand side matrix B.
On exit, if INFO = 0, the NbyNRHS 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 ith argument had an illegal value
> 0: if INFO = i, the leading minor of order i is not
positive definite, and the solution has not been
computed. The factorization has not been completed
unless i = N.