Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?largv

Generates a vector of plane rotations with real cosines and real/complex sines.

Syntax

call slargv
(
n
,
x
,
incx
,
y
,
incy
,
c
,
incc
)
call dlargv
(
n
,
x
,
incx
,
y
,
incy
,
c
,
incc
)
call clargv
(
n
,
x
,
incx
,
y
,
incy
,
c
,
incc
)
call zlargv
(
n
,
x
,
incx
,
y
,
incy
,
c
,
incc
)
Include Files
  • mkl.fi
Description
The routine generates a vector of real/complex plane rotations with real cosines, determined by elements of the real/complex vectors
x
and
y
.
For
slargv
/
dlargv
:
Equation
For
clargv
/
zlargv
:
Equation
where
c
(i)
2
+ abs(s(i))
2
= 1
and the following conventions are used (these are the same as in
clartg
/
zlartg
but differ from the BLAS Level 1 routine
crotg
/
zrotg
):
If
y
i
= 0
, then
c
(
i
) = 1
and
s
(
i
) = 0
;
If
x
i
= 0
, then
c
(
i
) = 0
and
s
(
i
) is chosen so that
r
i
is real.
Input Parameters
n
INTEGER
. The number of plane rotations to be generated.
x
,
y
REAL
for
slargv
DOUBLE PRECISION
for
dlargv
COMPLEX
for
clargv
DOUBLE COMPLEX
for
zlargv
Arrays,
DIMENSION
(1+(
n
-1)*
incx
) and (1+(
n
-1)*
incy
), respectively. On entry, the vectors
x
and
y
.
incx
INTEGER
. The increment between elements of
x
.
incx
> 0
.
incy
INTEGER
. The increment between elements of
y
.
incy
> 0
.
incc
INTEGER
. The increment between elements of the output array
c
.
incc
> 0
.
Output Parameters
x
On exit,
x
(
i
) is overwritten by
a
i
(for real flavors), or by
r
i
(for complex flavors), for
i
= 1,...,
n
.
y
On exit, the sines
s
(
i
) of the plane rotations.
c
REAL
for
slargv
/
clargv
DOUBLE PRECISION
for
dlargv
/
zlargv
Array,
DIMENSION
(1+(
n
-1)*
incc
). The cosines of the plane rotations.