Intel® oneAPI Math Kernel Library (oneMKL) - Data Parallel C++ Developer Reference
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Visible to Intel only — GUID: GUID-1842A682-8FA6-40E7-8626-1FA5F8CCF4D9
getrf_batch (Buffer Strided Version)
Computes the batch of LU factorizations of a batch of general m-by-n matrices. This routine belongs to the oneapi::mkl::lapack namespace.
Description
The routine computes the LU factorizations of a batch of general m-by-n matrices Ai, as:
Where Pi is a permutation matrix, Li is lower triangular with unit diagonal elements (lower trapezoidal if m > n) and Ui is upper triangular (upper trapezoidal if m < n). The routine uses partial pivoting with row interchanges.
API
Syntax
namespace oneapi::mkl::lapack {
void getrf_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<std::int64_t> &ipiv,
std::int64_t stride_ipiv,
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_ipiv
-
The stride between the beginnings of arrays ipivi inside the array ipiv.
- 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 getrf_batch_scratchpad_size (Strided Version).
Output Parameters
- a
-
Overwritten by Li and Ui. The unit diagnonal elements of Li are not stored.
- ipiv
-
Array containing the batch of the pivot indices ipivi each of size at least max(1,min(m,n)); for 1 ≤ k ≤ min(m,n), row k of Ai was interchanged with row ipivi(k).
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. If info is zero, then the diagonal element of some of Ui is zero, and the solve could not be completed. The indexes of such matrices in the batch can be obtained with the ids() method of the exception object. You can obtain the indexes of the first zero diagonal elements in these Ui matrices using the infos() method of the exception object. |