NAME¶

DPTTRSV - solve one of the triangular systems L**T* X = B, or L * X = B,

SYNOPSIS¶

SUBROUTINE DPTTRSV(

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

CHARACTER TRANS INTEGER INFO, LDB, N, NRHS DOUBLE PRECISION D( * ) DOUBLE PRECISION B( LDB, * ), E( * )

PURPOSE¶

DPTTRSV solves one of the triangular systems
L**T* X = B, or L * X = B, where L is the Cholesky factor of a Hermitian positive
definite tridiagonal matrix A such that
A = L*D*L**H (computed by DPTTRF).

ARGUMENTS¶

TRANS (input) CHARACTER

Specifies the form of the system of equations:
= 'N': L * X = B (No transpose)
= 'T': L**T * X = B (Transpose)

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 DPTTRF.

E (input) COMPLEX array, dimension (N-1)

The (n-1) off-diagonal elements of the unit bidiagonal factor U or L from the factorization computed by DPTTRF (see UPLO).

B (input/output) COMPLEX 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