orgqr_batch (Group Version)
Generates the real orthogonal matrices
Q
i
of the batch of QR factorizations formed by geqrf_batch
(Group Version). This routine belongs to the oneapi::mkl::lapack
namespace.Description
The routine generates the wholes or parts of the
m
-by-m
orthogonal matrices Q
1
of the batch of QR factorizations
formed by the routine geqrf_batch (Group Version).
Usually, Q
1
is determined from the QR factorization of
an m
-by-p
matrix A
1
with m
≥p
.To compute the whole matrices
Q
1
, use:orgqr_batch(queue, m, m, p, a, ...)
To compute the leading
p
columns of Q
1
(which form
an orthonormal basis in the space spanned by the columns of
A
1
):orgqr_batch(queue, m, p, p, a, ...)
To compute the matrices
Q
1
k
of the QR
factorizations of leading k
columns of the matrices
A
1
:orgqr_batch(queue, m, m, k, a, ...)
To compute the leading
k
columns of Q
1
k
(which form an orthonormal basis in the space spanned by leading
k
columns of the matrices A
1
):orgqr_batch(queue, m, k, k, a, ...)
API
Syntax
namespace oneapi::mkl::lapack {
cl::sycl::event orgqr_batch(cl::sycl::queue &queue,
std::int64_t *m,
std::int64_t *n,
std::int64_t *k,
T **a,
std::int64_t *lda,
T **tau,
std::int64_t group_count,
std::int64_t *group_sizes,
T *scratchpad,
std::int64_t scratchpad_size,
const std::vector<cl::sycl::event> &events = {})
}
Function supports the following precisions and devices.
T | Devices supported |
---|---|
float | Host, CPU, and GPU |
double | Host, CPU, and GPU |
Input Parameters
- queue
- Device queue where calculations will be performed.
- m
- n
- k
- Array ofgroup_countparameterskgas previously supplied to geqrf_batch (Group Version). The number of elementary reflectors whose product defines the matricesQi(0 ≤kg≤ng) .
- a
- Array resulting after a call togeqrf_batch (Group Version) <geqrf_batch-group-version.
- lda
- tau
- Array resulting after a call to geqrf_batch (Group Version).
- group_count
- Specifies the number of groups of parameters. Must be at least 0.
- group_sizes
- Array of group_count integers. Array element with indexgspecifies the number of problems to solve for each of the groups of parametersg. So the total number of problems to solve,batch_size, is a sum of all parameter group sizes.
- 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 then the value returned by orgqr_batch_scratchpad_size (Group Version).
- events
- List of events to wait for before starting computation. Defaults to empty list.
Output Parameters
- a
- Matrices pointed to by arrayaare overwritten byngleading columns of themg-by-mgorthogonal matricesQi, wheregis an index of group of parameters corresponding toQi.
Exceptions
Exception | Description |
---|---|
mkl::lapack::batch_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 info = -n , the n -th parameter had an illegal value.If info equals the value passed as scratchpad size, and detail() returns non-zero, then the passed scratchpad is of insufficient size, and the required size should be not less then value returned by the detail() method of the exception object. |
Return Values
Output event to wait on to ensure computation is complete.