rotm#
Performs modified Givens rotation of points in the plane.
Description
Given two vectors x
and y
, each vector element of these
vectors is replaced as follows:
for i
from 1 to n
, where H
is a modified Givens
transformation matrix.
rotm
supports the following precisions.
T
float
double
rotm (Buffer Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
void rotm(sycl::queue &queue,
std::int64_t n,
sycl::buffer<T,1> &x,
std::int64_t incx,
sycl::buffer<T,1> &y,
std::int64_t incy,
sycl::buffer<T,1> ¶m)
}
namespace oneapi::mkl::blas::row_major {
void rotm(sycl::queue &queue,
std::int64_t n,
sycl::buffer<T,1> &x,
std::int64_t incx,
sycl::buffer<T,1> &y,
std::int64_t incy,
sycl::buffer<T,1> ¶m)
}
Input Parameters
- queue
The queue where the routine should be executed.
- n
Number of elements in vector
x
.- x
Buffer holding input vector
x
. The buffer must be of size at least (1 + (n
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
Stride of vector
x
.- y
Buffer holding input vector
x
. The buffer must be of size at least (1 + (n
- 1)*abs(incy
)). See Matrix Storage for more details.- incy
Stride of vector
y
.- param
Buffer holding an array of size 5.
The elements of the
param
array are:param[0]
contains a switch,flag
. The other array elementsparam[1-4]
contain the components of the modified Givens transformation matrixH
: h11, h21, h12, and h22, respectively.Depending on the values of
flag
, the components ofH
are set as follows:flag = -1.0
:\[\begin{split}H=\begin{bmatrix}h_{11} & h_{12} \\ h_{21} & h_{22}\end{bmatrix}\end{split}\]flag = 0.0
:\[\begin{split}H=\begin{bmatrix}1.0 & h_{12} \\ h_{21} & 1.0\end{bmatrix}\end{split}\]flag = 1.0
:\[\begin{split}H=\begin{bmatrix}h_{11} & 1.0 \\ -1.0 & h_{22}\end{bmatrix}\end{split}\]flag = -2.0
:\[\begin{split}H=\begin{bmatrix}1.0 & 0.0 \\ 0.0 & 1.0\end{bmatrix}\end{split}\]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 theparam
vector.
Output Parameters
- x
Buffer holding updated buffer
x
.- y
Buffer holding updated buffer
y
.
rotm (USM Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
sycl::event rotm(sycl::queue &queue,
std::int64_t n,
T *x,
std::int64_t incx,
T *y,
std::int64_t incy,
T *param,
const std::vector<sycl::event> &dependencies = {})
}
namespace oneapi::mkl::blas::row_major {
sycl::event rotm(sycl::queue &queue,
std::int64_t n,
T *x,
std::int64_t incx,
T *y,
std::int64_t incy,
T *param,
const std::vector<sycl::event> &dependencies = {})
}
Input Parameters
- queue
The queue where the routine should be executed.
- n
Number of elements in vector
x
.- x
Pointer to the input vector
x
. The array holding the vectorx
must be of size at least (1 + (n
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
Stride of vector
x
.- yparam
Pointer to the input vector
y
. The array holding the vectory
must be of size at least (1 + (n
- 1)*abs(incy
)). See Matrix Storage for more details.- incy
Stride of vector
y
.- param
Buffer holding an array of size 5.
The elements of the
param
array are:param[0]
contains a switch,flag
. The other array elementsparam[1-4]
contain the components of the modified Givens transformation matrixH
: h11, h21, h12, and h22, respectively.Depending on the values of
flag
, the components ofH
are set as follows:flag = -1.0
:\[\begin{split}H=\begin{bmatrix}h_{11} & h_{12} \\ h_{21} & h_{22}\end{bmatrix}\end{split}\]flag = 0.0
:\[\begin{split}H=\begin{bmatrix}1.0 & h_{12} \\ h_{21} & 1.0\end{bmatrix}\end{split}\]flag = 1.0
:\[\begin{split}H=\begin{bmatrix}h_{11} & 1.0 \\ -1.0 & h_{22}\end{bmatrix}\end{split}\]flag = -2.0
:\[\begin{split}H=\begin{bmatrix}1.0 & 0.0 \\ 0.0 & 1.0\end{bmatrix}\end{split}\]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 theparam
vector.- dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
- x
Pointer to the updated array
x
.- y
Pointer to the updated array
y
.
Return Values
Output event to wait on to ensure computation is complete.
Parent topic: BLAS Level 1 Routines