Provided by: scalapack-doc_1.5-10_all

**NAME**

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

**SYNOPSIS**

SUBROUTINE SPTTRSV( TRANS, N, NRHS, D, E, B, LDB, INFO ) CHARACTER TRANS INTEGER INFO, LDB, N, NRHS REAL D( * ) REAL B( LDB, * ), E( * )

**PURPOSE**

SPTTRSV 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 SPTTRF).

**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 SPTTRF. 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 SPTTRF (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