Function

NumCosmoMathlapack_dgerqf

Declaration [src]

gint
ncm_lapack_dgerqf (
  gint m,
  gint n,
  gdouble* a,
  gint lda,
  gdouble* tau,
  NcmLapackWS* ws
)

Description [src]

DGERQF computes a RQ factorization of a real M-by-N matrix A: A = R * Q.

Parameters

m

Type: gint

M is INTEGER The number of rows of the matrix A. M >= 0.

n

Type: gint

N is INTEGER The number of columns of the matrix A. N >= 0.

a

Type: gdouble*

A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the M-by-N matrix A. On exit, the elements on and above the diagonal of the array contain the min(M,N)-by-N upper trapezoidal matrix R (R is upper triangular if m >= n); the elements below the diagonal, with the array TAU, represent the orthogonal matrix Q as a product of min(m,n) elementary reflectors (see Further Details).

The data is owned by the caller of the function.

lda

Type: gint

LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).

tau

Type: gdouble*

TAU is DOUBLE PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details).

The data is owned by the caller of the function.

ws

Type: NcmLapackWS

A NcmLapackWS.

The data is owned by the caller of the function.

Return value

Type: gint

= 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value.