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Visible to Intel only — GUID: GUID-77AE1CBF-0A4B-414C-B461-C3376634D1A5
Visible to Intel only — GUID: GUID-77AE1CBF-0A4B-414C-B461-C3376634D1A5
getrf_batch (Group 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, (iϵ{1...batch_size}) 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.
Total number of problems to solve, batch_size, is a sum of sizes of all of the groups of parameters as provided by group_sizes array.
API
Syntax
namespace oneapi::mkl::lapack { sycl::event getrf_batch(sycl::queue &queue, int64_t *m, int64_t *n, T **a, int64_t *lda, int64_t **ipiv, int64_t group_count, int64_t *group_sizes, T *scratchpad, int64_t scratchpad_size, const std::vector<sycl::event> &events = {}) }
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
-
Array of group_count parameters mg specifying the number of rows in the matrices Ai belonging to group g (mg ≥ 0).
- n
-
Array of group_count parameters ng specifying the number of columns in the matrices Ai belonging to group g (ng ≥ 0).
- a
-
Array of batch_size pointers to input matricesAi. The pointers must be device-accessible.
- lda
-
Array of group_count parameters ldag specifying the leading dimension of Ai belonging to group g (ldag ≥ max(1, mg)).
- group_count
-
Specifies the number of groups of parameters. Must be at least 0.
- group_sizes
-
Array of group_count integers. Array element with index g specifies the number of problems to solve for each of the groups of parameters g. 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 getrf_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 array a are overwritten by Li and Ui. The unit diagonal elements of Li are not stored.
- ipiv
-
Arrays of batch_size pointers to arrays containing pivot indices ipivi each of size at least max(1,min(mg, ng)); for 1 ≤ k ≤ min(mg, ng), row k of Ai was interchanged with row ipivi(k). The pointers must be device-accessible.
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. |
Return Values
Output event to wait on to ensure computation is complete.