Visible to Intel only — GUID: GUID-10E5D95E-5EB2-4EB8-AE10-A6992E85F483
Visible to Intel only — GUID: GUID-10E5D95E-5EB2-4EB8-AE10-A6992E85F483
?larfp
Generates a real or complex elementary reflector.
call slarfp(n, alpha, x, incx, tau)
call dlarfp(n, alpha, x, incx, tau)
call clarfp(n, alpha, x, incx, tau)
call zlarfp(n, alpha, x, incx, tau)
- mkl.fi
The ?larfp routines generate a real or complex elementary reflector H of order n, such that
H * (alpha) = (beta), ( x ) ( 0 )
and H'*H =I for real flavors, conjg(H)'*H =I for complex flavors.
Here
alpha and beta are scalars, beta is real and non-negative,
x is (n-1)-element vector.
H is represented in the form
H = I - tau*( 1 )* (1 v'), ( v )
where tau is scalar, and v is (n-1)-element vector .
For real flavors if the elements of x are all zero, then tau = 0 and H is taken to be the unit matrix. Otherwise 1 ≤tau≤ 2.
For complex flavors if the elements of x are all zero and alpha is real, then tau = 0 and H is taken to be the unit matrix. Otherwise 1 ≤ real(tau) ≤ 2, and abs (tau-1≤ 1.
- n
-
INTEGER. Specifies the order of the elementary reflector.
- alpha
-
REAL for slarfp
DOUBLE PRECISION for dlarfp
COMPLEX for clarfp
DOUBLE COMPLEX for zlarfp
Specifies the scalar alpha.
- x
-
REAL for slarfp
DOUBLE PRECISION for dlarfp
COMPLEX for clarfp
DOUBLE COMPLEX for zlarfp
Array, DIMENSION at least (1 + (n - 1)*abs(incx)). It contains the vector x.
- incx
-
INTEGER. Specifies the increment for the elements of x.
The value of incx must not be zero.
- alpha
-
Overwritten by the value beta.
- y
-
Overwritten by the vector v.
- tau
-
REAL for slarfp
DOUBLE PRECISION for dlarfp
COMPLEX for clarfp
DOUBLE COMPLEX for zlarfp
Contains the scalar tau.