Contents

# rotg

Computes the parameters for a Givens rotation.

## Description

Given the Cartesian coordinates
(a, b)
of a point, the
rotg
routines return the parameters
c
,
s
,
r
, and
z
associated with the Givens rotation. The parameters
c
and
s
define a unitary matrix such that:
The parameter
z
is defined such that if |
a
| > |
b
|,
z
is
s
; otherwise if
c
is not 0
z
is 1/
c
; otherwise
z
is 1.
rotg
supports the following precisions:
T
T_real
float
float
double
double
std::complex<float>
float
std::complex<double>
double

## rotg (Buffer Version)

Syntax
``````namespace oneapi::mkl::blas::column_major {
void rotg(sycl::queue &queue,
sycl::buffer<T,1> &a,
sycl::buffer<T,1> &b,
sycl::buffer<T_real,1> &c,
sycl::buffer<T,1> &s)
}``````
``````namespace oneapi::mkl::blas::row_major {
void rotg(sycl::queue &queue,
sycl::buffer<T,1> &a,
sycl::buffer<T,1> &b,
sycl::buffer<T_real,1> &c,
sycl::buffer<T,1> &s)
}``````
Input Parameters
queue
The queue where the routine should be executed
a
Buffer holding
x
-coordinate of the point.
b
Buffer holding
y
-coordinate of the point.
Output Parameters
a
Buffer holding parameter
r
associated with the Givens rotation.
b
Buffer holding parameter
z
associated with the Givens rotation.
c
Buffer holding parameter
c
associated with the Givens rotation.
s
Buffer holding parameter
s
associated with the Givens rotation.

## rotg (USM Version)

Syntax
``````namespace oneapi::mkl::blas::column_major {
sycl::event rotg(sycl::queue &queue,
T *a,
T *b,
T_real *c,
T *s,
const std::vector<sycl::event> &dependencies = {})
}``````
``````namespace oneapi::mkl::blas::row_major {
sycl::event rotg(sycl::queue &queue,
T *a,
T *b,
T_real *c,
T *s,
const std::vector<sycl::event> &dependencies = {})
}``````
Input Parameters
queue
The queue where the routine should be executed
a
Pointer to
x
-coordinate of the point.
b
Pointer to
y
-coordinate of the point.
dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
a
Pointer to parameter
r
associated with the Givens rotation.
b
Pointer to parameter
z
associated with the Givens rotation.
c
Pointer to parameter
c
associated with the Givens rotation.
s
Pointer to parameter
s
associated with the Givens rotation.
Return Values
Output event to wait on to ensure computation is complete.

#### Product and Performance Information

1

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