unmrq¶
Multiplies a complex matrix by the unitary matrix Q of the RQ
factorization formed by gerqf. This routine belongs to the
oneapi::mkl::lapack
namespace.
Syntax
namespace oneapi::mkl::lapack {
void unmrq(cl::sycl::queue &queue, mkl::side side, mkl::transpose trans, std::int64_t m, std::int64_t n, std::int64_t k, cl::sycl::buffer<T> &a, std::int64_t lda, cl::sycl::buffer<T> &tau, cl::sycl::buffer<T> &c, std::int64_t ldc, cl::sycl::buffer<T> &scratchpad, std::int64_t scratchpad_size)
}
unmrq
supports the following precisions and devices:
T |
Devices supported |
---|---|
|
Host and CPU |
|
Host and CPU |
Description
The routine multiplies a complex m
-by-n
matrix C
by Q
or Q
H, where Q
is the complex unitary matrix defined
as a product of k
elementary reflectors H(i)
of order n
:
Q = H(1)H* H(2)
H*…*H(k)H
as returned by the
RQ
factorization routine
gerqf
.
Depending on the parameters side
and trans
, the routine can
form one of the matrix products Q*C
, Q
H*C
,
C*Q
, or C*Q
H (overwriting the result over C
).
Input Parameters
- queue
Device queue where calculations will be performed.
- side
If
side
=mkl::side::left
,Q
orQ
T is applied toC
from the left. Ifside
=mkl::side::right
,Q
orQ
T is applied toC
from the right.- trans
If
trans=mkl::transpose::trans
, the routine multipliesC
byQ
.If
trans=mkl::transpose::nontrans
, the routine multipliesC
byQ
T.- m
The number of rows in the matrix
A
(0≤m
).- n
The number of columns in the matrix
A
(0≤n≤m
).- k
The number of elementary reflectors whose product defines the matrix
Q
(0≤k≤n
).- a
Buffer holding the result of the gerqf function. The second dimension of
a
must be at leastmax(1,k)
.- lda
The leading dimension of a.
- tau
Buffer holding tau returned by the gerqf function.
- c
Buffer holding the matrix
C
. The second dimension of c must be at leastmax(1,n)
.- ldc
The leading dimension of c.
- scratchpad
Buffer holding scratchpad memory to be used by the routine for storing intermediate results.
- scratchpad_size
Size of scratchpad memory as a number of floating point elements of type
T
. Size should not be less than the value returned by the unmrq_scratchpad_size function.
Output Parameters
- c
Overwritten by the product
Q
*C
,Q
T*C
,C
*Q
, orC
*Q
T (as specified by side and trans).
Exceptions
mkl::lapack::exception |
This exception is thrown when problems occur during calculations. You can obtain the info code of the problem using the info() method of the exception object: If |