DPTTRS(3F)DPTTRS(3F)NAME
DPTTRS - 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 DPTTRF
SYNOPSIS
SUBROUTINE DPTTRS( N, NRHS, D, E, B, LDB, INFO )
INTEGER INFO, LDB, N, NRHS
DOUBLE PRECISION B( LDB, * ), D( * ), E( * )
PURPOSE
DPTTRS 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 DPTTRF. (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) DOUBLE PRECISION array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization computed by DPTTRF.
E (input) DOUBLE PRECISION array, dimension (N-1)
The (n-1) off-diagonal elements of the unit bidiagonal factor U
or L from the factorization computed by DPTTRF.
B (input/output) DOUBLE PRECISION 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
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