getrf_batch (Buffer Strided Version)
Computes the batch of LU factorizations of a 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 A
i
, as:
Where
P
i
is a permutation matrix, L
i
is
lower triangular with unit diagonal elements (lower trapezoidal if
m > n
) and U
i
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(
cl::sycl::queue &queue,
std::int64_t m,
std::int64_t n,
cl::sycl::buffer<T> &a,
std::int64_t lda,
std::int64_t stride_a,
cl::sycl::buffer<std::int64_t> &ipiv,
std::int64_t stride_ipiv,
std::int64_t batch_size,
cl::sycl::buffer<T> &scratchpad,
std::int64_t scratchpad_size)
}
Function supports the following precisions and devices.
T | Devices supported |
---|---|
float | Host, CPU, and GPU |
double | Host, CPU, and GPU |
std::complex<float> | Host, CPU, and GPU |
std::complex<double> | Host, CPU, and GPU |
Input Parameters
- queue
- Device queue where calculations will be performed.
- m
- The number of rows in the matricesAi(0 ≤ m).
- n
- The number of columns in the matricesAi(0 ≤ n).
- a
- Array holding input matricesAi.
- lda
- The leading dimension ofAi.
- stride_a
- The stride between the beginnings of matricesAiinside the batch arraya.
- stride_ipiv
- The stride between the beginnings of arraysipiviinside the arrayipiv.
- batch_size
- Specifies 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 typeT. Size should not be less than the value returned by getrf_batch_scratchpad_size (Strided Version).
Output Parameters
- a
- Overwritten byLiandUi. The unit diagnonal elements ofLiare not stored.
- ipiv
- Array containing the batch of the pivot indicesipivieach of size at leastmax(1,min(m,n)); for 1 ≤k≤min(m,n), rowkofAiwas interchanged with rowipivi(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 U i 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 U i matrices using the infos() method of the exception object. |