Provided by: liblapack-doc_3.3.1-1_all NAME

LAPACK-3  - computes the solution to a real system of linear equations A*X = B, where A is
an N-by-N symmetric positive definite tridiagonal  matrix,  and  X  and  B  are  N-by-NRHS
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 N-
by-N symmetric positive definite tridiagonal matrix, and X and B are N-by-NRHS 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 (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A.  On exit, the (n-1) 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 N-by-NRHS right hand side matrix B.
On exit, if INFO = 0, the N-by-NRHS 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
> 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.

LAPACK routine (version 3.3.1)             April 2011                             DPTSV(3lapack)