orgqr_batch (Buffer Strided Version)¶
Generates the real orthogonal matrices Q
i of the batch QR
factorizations formed by geqrf_batch
(Buffer Strided Version). This
routine belongs to the oneapi::mkl::lapack
namespace.
Description¶
The routine generates the wholes or parts of the orthogonal matrices
Q
i of the batch of QR factorizations formed by the
routine geqrf_batch (Buffer Strided Version).
Usually, Q
i is determined from the QR factorization of
an m
-by-p
matrix A
i with m
≥ p
.
To compute the whole matrices Q
i, use:
orgqr_batch(queue, m, m, p, a, ...)
To compute the leading p
columns of Q
i (which form
an orthonormal basis in the space spanned by the columns of
A
i):
orgqr_batch(queue, m, p, p, a, ...)
To compute the matrices Q
ik of the QR
factorizations of leading k
columns of the matrices
A
i:
orgqr_batch(queue, m, m, k, a, ...)
To compute the leading k
columns of Q
ik
(which form an orthonormal basis in the space spanned by leading
k
columns of the matrices A
i):
orgqr_batch(queue, m, k, k, a, ...)
API¶
Syntax¶
namespace oneapi::mkl::lapack {
void orgqr_batch(sycl::queue &queue,
std::int64_t m,
std::int64_t n,
std::int64_t k,
sycl::buffer<T> &a,
std::int64_t lda,
std::int64_t stride_a,
sycl::buffer<T> &tau,
std::int64_t stride_tau,
std::int64_t batch_size,
sycl::buffer<T> &scratchpad,
std::int64_t scratchpad_size)
}
This function supports the following precisions and devices:
T |
Devices supported |
---|---|
|
CPU and GPU |
|
CPU and GPU |
Input Parameters¶
- queue
Device queue where calculations will be performed.
- m
The number of rows in the matrices
A
i (m ≥ 0
).- n
The number of columns in the matrices
A
i (n ≥ 0
).- k
the number of elementary reflectors whose product defines the matrices
Q
i (0 ≤k
≤n
) .- a
Array resulting after a call to geqrf_batch (Buffer Strided Version).
- lda
The leading dimension of
A
i (lda
≥max(1,m)
).- stride_a
The stride between the beginnings of matrices
A
i inside the batch arraya
(stride_a
≥max(1, lda * n)
).- tau
Array resulting after a call to geqrf_batch (Buffer Strided Version).
- stride_tau
The stride between the beginnings of arrays
tau
i inside the arraytau
(stride_tau
≥max(1, min(m,n))
).- batch_size
The number of problems in a batch (
batch_size
≥ 0).- scratchpad
Scratchpad memory to be used by 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 orgqr_batch_scratchpad_size (Strided Version).
Output Parameters¶
- a
Array data is overwritten by a batch of
n
leading columns of them
-by-m
orthogonal matricesQ
i.
Exceptions¶
Exception |
Description |
---|---|
|
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 If |