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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine dlaptm | ( | integer | N, |
integer | NRHS, | ||
double precision | ALPHA, | ||
double precision, dimension( * ) | D, | ||
double precision, dimension( * ) | E, | ||
double precision, dimension( ldx, * ) | X, | ||
integer | LDX, | ||
double precision | BETA, | ||
double precision, dimension( ldb, * ) | B, | ||
integer | LDB | ||
) |
DLAPTM
DLAPTM multiplies an N by NRHS matrix X by a symmetric tridiagonal matrix A and stores the result in a matrix B. The operation has the form B := alpha * A * X + beta * B where alpha may be either 1. or -1. and beta may be 0., 1., or -1.
[in] | N | N is INTEGER The order of the matrix A. N >= 0. |
[in] | NRHS | NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrices X and B. |
[in] | ALPHA | ALPHA is DOUBLE PRECISION The scalar alpha. ALPHA must be 1. or -1.; otherwise, it is assumed to be 0. |
[in] | D | D is DOUBLE PRECISION array, dimension (N) The n diagonal elements of the tridiagonal matrix A. |
[in] | E | E is DOUBLE PRECISION array, dimension (N-1) The (n-1) subdiagonal or superdiagonal elements of A. |
[in] | X | X is DOUBLE PRECISION array, dimension (LDX,NRHS) The N by NRHS matrix X. |
[in] | LDX | LDX is INTEGER The leading dimension of the array X. LDX >= max(N,1). |
[in] | BETA | BETA is DOUBLE PRECISION The scalar beta. BETA must be 0., 1., or -1.; otherwise, it is assumed to be 1. |
[in,out] | B | B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the N by NRHS matrix B. On exit, B is overwritten by the matrix expression B := alpha * A * X + beta * B. |
[in] | LDB | LDB is INTEGER The leading dimension of the array B. LDB >= max(N,1). |
Definition at line 118 of file dlaptm.f.