Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

cblas_?rotm

Performs modified Givens rotation of points in the plane.

Syntax

void
cblas_srotm
(
const
MKL_INT
n
,
float
*x
,
const
MKL_INT
incx
,
float
*y
,
const
MKL_INT
incy
,
const
float
*param
);
void
cblas_drotm
(
const
MKL_INT
n
,
double
*x
,
const
MKL_INT
incx
,
double
*y
,
const
MKL_INT
incy
,
const
double
*param
);
Include Files
  • mkl.h
Description
Given two vectors
x
 and
y
, each vector element of these vectors is replaced as follows:
for
i
=1 to
n
, where
H
 is a modified Givens transformation matrix whose values are stored in the
param
[1]
 through
param
[4]
 array. See discussion on the
param
 argument.
Input Parameters
n
Specifies the number of elements in vectors
x
 and
y
.
x
Array, size at least
(1 + (
n
 -1)*abs(
incx
))
.
incx
Specifies the increment for the elements of
x
.
y
Array, size at least
(1 + (
n
 -1)*abs(
incy
))
.
incy
Specifies the increment for the elements of
y
.
param
Array, size 5.
The elements of the
param
 array are:
param
[0]
 contains a switch,
flag
.
param
[1-4]
 contain
h
11
,
h
21
,
h
12
, and
h
22
, respectively, the components of the array
H
.
Depending on the values of
flag
, the components of
H
 are set as follows:
flag
 =
-1.0
:
flag
 =
0.0
:
flag
 =
1.0
:
flag
 =
-2.0
:
In the last three cases, the matrix entries of 1.0, -1.0, and 0.0 are assumed based on the value of
flag
 and are not required to be set in the
param
 vector.
Output Parameters
x
Each element
x[i]
 is replaced by
h
11
*
x[i]
 +
h
12
*
y[i]
.
y
Each element
y[i]
 is replaced by
h
21
*
x[i]
 +
h
22
*
y[i]
.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.