Developer Reference

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

?lartgp

Generates a plane rotation.

Syntax

call slartgp
(
f
,
g
,
cs
,
sn
,
r
)
call dlartgp
(
f
,
g
,
cs
,
sn
,
r
)
call lartgp
(
f
,
g
,
cs
,
sn
,
r
)
Include Files
  • mkl.fi
Description
The routine generates a plane rotation so that
Equation
where
cs
2
+
sn
2
= 1
This is a slower, more accurate version of the BLAS Level 1 routine
?rotg
, except for the following differences:
  • f
    and
    g
    are unchanged on return.
  • If
    g
    =0, then
    cs
    =(+/-)1 and
    sn
    =0.
  • If
    f
    =0 and
    g
    0, then
    cs
    =0 and
    sn
    =(+/-)1.
The sign is chosen so that
r
0.
Input Parameters
The data types are given for the Fortran interface.
f
,
g
REAL
for
slartgp
DOUBLE PRECISION
for
dlartgp
The first and second component of the vector to be rotated.
Output Parameters
cs
REAL
for
slartgp
DOUBLE PRECISION
for
dlartgp
The cosine of the rotation.
sn
REAL
for
slartgp
DOUBLE PRECISION
for
dlartgp
The sine of the rotation.
r
REAL
for
slartgp
DOUBLE PRECISION
for
dlartgp
The nonzero component of the rotated vector.
info
INTEGER
.
If
info
= 0
, the execution is successful.
If
info
=-1
,
f
is NaN.
If
info
= -2
,
g
is NaN.
LAPACK 95 Interface Notes
Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see LAPACK 95 Interface Conventions.
Specific details for the routine
?lartgp
interface are as follows:
f
Holds the first component of the vector to be rotated.
g
Holds the second component of the vector to be rotated.
cs
Holds the cosine of the rotation.
sn
Holds the sine of the rotation.
r
Holds the nonzero component of the rotated vector.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on mi