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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
|
| subroutine dlarfx | ( | character | SIDE, |
| integer | M, | ||
| integer | N, | ||
| double precision, dimension( * ) | V, | ||
| double precision | TAU, | ||
| double precision, dimension( ldc, * ) | C, | ||
| integer | LDC, | ||
| double precision, dimension( * ) | WORK | ||
| ) |
DLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.
Download DLARFX + dependencies [TGZ] [ZIP] [TXT]
DLARFX applies a real elementary reflector H to a real m by n
matrix C, from either the left or the right. H is represented in the
form
H = I - tau * v * v**T
where tau is a real scalar and v is a real vector.
If tau = 0, then H is taken to be the unit matrix
This version uses inline code if H has order < 11. | [in] | SIDE | SIDE is CHARACTER*1
= 'L': form H * C
= 'R': form C * H |
| [in] | M | M is INTEGER
The number of rows of the matrix C. |
| [in] | N | N is INTEGER
The number of columns of the matrix C. |
| [in] | V | V is DOUBLE PRECISION array, dimension (M) if SIDE = 'L'
or (N) if SIDE = 'R'
The vector v in the representation of H. |
| [in] | TAU | TAU is DOUBLE PRECISION
The value tau in the representation of H. |
| [in,out] | C | C is DOUBLE PRECISION array, dimension (LDC,N)
On entry, the m by n matrix C.
On exit, C is overwritten by the matrix H * C if SIDE = 'L',
or C * H if SIDE = 'R'. |
| [in] | LDC | LDC is INTEGER
The leading dimension of the array C. LDA >= (1,M). |
| [out] | WORK | WORK is DOUBLE PRECISION array, dimension
(N) if SIDE = 'L'
or (M) if SIDE = 'R'
WORK is not referenced if H has order < 11. |