potrf_batch (Group Version)#
Computes the Cholesky factorizations of a batch of symmetric (or
Hermitian, for complex data) positive-definite matrices. This routine
belongs to the oneapi::mkl::lapack namespace.
Description#
The routine forms the Cholesky factorizations of a symmetric
positive-definite or, for complex data, Hermitian positive-definite
matrices Ai, iϵ{1...batch_size}:
Ai =UiT *Ui for real data,Ai =UiH *Ui for complex data. ifuplog = mkl::uplo::upper,Ai =LiT *Li for real data,Ai =LiH *Li for complex data ifuplog = mkl::uplo::lower
Where Li is a lower triangular matrix and
Ui is an upper triangular matrix, g is an index of
group of parameters corresponding to Ai, and the total
number of problems to solve, batch_size, is a sum of sizes for
all of the groups of parameters as provided by the group_sizes
array.
API#
Syntax#
namespace oneapi::mkl::lapack {
sycl::event potrf_batch(sycl::queue &queue,
mkl::uplo *uplo,
int64_t *n,
T **a,
int64_t *lda,
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 |
|---|---|
|
CPU and GPU |
|
CPU and GPU |
|
CPU and GPU |
|
CPU and GPU |
Input Parameters#
- queue
Device queue where calculations will be performed.
- uplo
Array of
group_countuplog parameters.Each of uplog indicates whether the upper or lower triangular parts of the input matrices are provided:
If uplog=
mkl::uplo::upper, input matrices from arrayabelonging to groupgstore the upper triangular parts.If uplog=
mkl::uplo::lower, input matrices from arrayabelonging to groupgstore the lower triangular parts.- n
Array of
group_countparametersng.Each
ng specifies the order of the input matrices from arrayabelonging to groupg(ng ≥ 0).- a
Array of
batch_sizepointers to input matricesAi, each being of sizeldag*ng (gis an index of the group to whichAi belongs) and holding either upper or lower triangular part as specified by uplog.- lda
Array of
group_countparameters ldag.Each ldag specifies the leading dimension of matrices from
abelonging to groupg(ldag ≥max(1, ng)).- 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
gspecifies 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 potrf_batch_scratchpad_size (Group Version).
- events
List of events to wait for before starting computation. Defaults to empty list.
Output Parameters#
- a
The matrices pointed to by array a are overwritten by the Cholesky factors
Ui orLi, as specified by uplog from the corresponding group of parameters.
Exceptions#
Exception |
Description |
|---|---|
|
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 If If |
Return Values#
Output event to wait on to ensure computation is complete.