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Visible to Intel only — GUID: GUID-69FA39F5-E13A-49E8-893E-7C76BFAD8E78
Visible to Intel only — GUID: GUID-69FA39F5-E13A-49E8-893E-7C76BFAD8E78
geqrf_batch (Buffer Strided Version)
Computes the batch of QR factorizations of a batch of general m-by-n matrices. This routine belongs to the oneapi::mkl::lapack namespace.
Description
The routine forms the QiRi factorizations of a general m-by-n matrices Ai. No pivoting is performed.
The routine does not form the matrix Qi explicitly. Instead, Qi is represented as a product of min(m, n) elementary reflectors. Routines are provided to work with Qi in this representation.
API
Syntax
namespace oneapi::mkl::lapack {
void geqrf_batch(sycl::queue &queue,
std::int64_t m,
std::int64_t n,
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 |
|---|---|
float |
CPU and GPU |
double |
CPU and GPU |
std::complex<float> |
CPU and GPU |
std::complex<double> |
CPU and GPU |
Input Parameters
- queue
-
Device queue where calculations will be performed.
- m
-
The number of rows in the matrices Ai (0 ≤ m).
- n
-
The number of columns in the matrices Ai (0 ≤ n).
- a
-
Array holding input matrices Ai.
- lda
-
The leading dimension of Ai .
- stride_a
-
The stride between the beginnings of matrices Ai inside the batch array a.
- stride_tau
-
The stride between the beginnings of arrays taui inside the array tau.
- batch_size
-
The number of problems in a batch.
- 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 geqrf_batch_scratchpad_size (Strided Version).
Output Parameters
- a
-
Overwritten by the factorization data as follows:
The elements on and above the diagonal of the array contain the min(m,n)-by-n upper trapezoidal matrices Ri (Ri is upper triangular if m ≥ n); the elements below the diagonal, with the array taui, present the orthogonal matrix Qi as a product of min(m,n) elementary reflectors.
- tau
-
Array to store batch of taui, each of size min(m,n), containing scalars that define elementary reflectors for the matrices Qi in its decomposition in a product of elementary reflectors.
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 than the value returned by the detail() method of the exception object. |