Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

Contents

cblas_?rotmg

Computes the parameters for a modified Givens rotation.

Syntax

void
cblas_srotmg
(
float
*d1
,
float
*d2
,
float
*x1
,
const
float
y1
,
float
*param
);
void
cblas_drotmg
(
double
*d1
,
double
*d2
,
double
*x1
,
const
double
y1
,
double
*param
);
Include Files
  • mkl.h
Description
Given Cartesian coordinates (
x1
,
y1
) of an input vector,
these
 routines compute the components of a modified Givens transformation matrix
H
 that zeros the
y
-component
of the resulting vector:
Input Parameters
d1
Provides the scaling factor for the
x
-coordinate of the input vector.
d2
Provides the scaling factor for the
y
-coordinate of the input vector.
x1
Provides the
x
-coordinate of the input vector.
y1
Provides the
y
-coordinate of the input vector.
Output Parameters
d1
Provides the first diagonal element of the updated matrix.
d2
Provides the second diagonal element of the updated matrix.
x1
Provides the
x
-coordinate of the rotated vector before scaling.
param
Array, size 5.
The elements of the
param
 array are:
param
[0]
 contains a switch,
flag
. the other array elements
param
[1-4]
 contain the components of the array
H
:
h
11
,
h
21
,
h
12
, and
h
22
, respectively.
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.

Product and Performance Information

1

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