CPTTS2 - solve a tridiagonal system of the form A * X = B
using the factorization A = U'*D*U or A = L*D*L' computed
by CPTTRF
SYNOPSIS
SUBROUTINE CPTTS2( IUPLO, N, NRHS, D, E, B, LDB )
INTEGER IUPLO, LDB, N, NRHS
REAL D( * )
COMPLEX B( LDB, * ), E( * )
PURPOSE
CPTTS2 solves a tridiagonal system of the form A * X = B
using the factorization A = U'*D*U or A = L*D*L' computed
by CPTTRF. D is a diagonal matrix specified in the vector
D, U (or L) is a unit bidiagonal matrix whose superdiago
nal (subdiagonal) is specified in the vector E, and X and
B are N by NRHS matrices.
ARGUMENTS
IUPLO (input) INTEGER
Specifies the form of the factorization and
whether the vector E is the superdiagonal of the
upper bidiagonal factor U or the subdiagonal of
the lower bidiagonal factor L. = 1: A = U'*D*U,
E is the superdiagonal of U
= 0: A = L*D*L', E is the subdiagonal of L
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 A = U'*D*U or A = L*D*L'.
E (input) COMPLEX array, dimension (N-1)
If IUPLO = 1, the (n-1) superdiagonal elements of
the unit bidiagonal factor U from the factoriza
tion A = U'*D*U. If IUPLO = 0, the (n-1) subdiag
onal elements of the unit bidiagonal factor L from
the factorization A = L*D*L'.
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the
system of linear equations. On exit, the solution
vectors, X.
The leading dimension of the array B. LDB >=
max(1,N).
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