potrf (USM Version)#
Computes the Cholesky factorization of a symmetric (Hermitian)
positive-definite matrix.This routine belongs to the
oneapi::mkl::lapack namespace.
Description#
The routine forms the Cholesky factorization of a symmetric
positive-definite or, for complex data, Hermitian positive-definite
matrix A:
|
if uplo= |
|
if uplo= |
where L is a lower triangular matrix and U is upper
triangular.
API#
Syntax#
namespace oneapi::mkl::lapack {
sycl::event potrf(sycl::queue &queue,
mkl::uplo uplo,
int64_t n,
T *a,
int64_t lda,
T *scratchpad,
int64_t scratchpad_size,
const std::vector<sycl::event> &events = {})
}
The USM version of potrf 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
Indicates whether the upper or lower triangular part of
Ais stored and howAis factored:If uplo=
mkl::uplo::upper, the arrayastores the upper triangular part of the matrixA, and the strictly lower triangular part of the matrix is not referenced.If uplo=
mkl::uplo::lower, the arrayastores the lower triangular part of the matrixA, and the strictly upper triangular part of the matrix is not referenced.- n
Specifies the order of the matrix
A(0 ≤ n).- a
Pointer to input matrix
A. The array holding input matrix a contains either the upper or the lower triangular part of the matrixA(see uplo). The size ofamust be at leastlda*n.- lda
The leading dimension of a.
- scratchpad
Pointer to scratchpad memory to be used by the 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 the potrf_scratchpad_size function.- events
List of events to wait for before starting computation. Defaults to empty list.
Output Parameters#
- a
The memory pointed to by pointer a is overwritten by the Cholesky factor
UorL, as specified by uplo.
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.