potri

oneMKL - Data Parallel C++ Developer Reference

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ID 772045

Date 3/31/2021

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potri

Computes the inverse of a symmetric (Hermitian) positive-definite matrix using the Cholesky factorization. This routine belongs to the oneapi::mkl::lapack namespace.

Description
API

Description

The routine computes the inverse inv(A) of a symmetric positive definite or, for complex flavors, Hermitian positive-definite matrix A. Before calling this routine, call potrf to factorize A.

API

Syntax

namespace oneapi::mkl::lapack {
  void potri(sycl::queue &queue,
  mkl::uplo uplo,
  std::int64_t n,
  sycl::buffer<T> &a,
  std::int64_t lda,
  sycl::buffer<T> &scratchpad,
  std::int64_t scratchpad_size)
}

potri 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.

uplo

Indicates how the input matrix A has been factored:

If uplo = mkl::uplo::upper, the upper triangle of A is stored.

If uplo = mkl::uplo::lower, the lower triangle of A is stored.

n

Specifies the order of the matrix A (0 ≤ n).

a

Contains the factorization of the matrix A, as returned by potrf (USM Version). The second dimension of a must be at least max(1, n).

lda

The leading dimension of a.

scratchpad

Buffer holding 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 potri_scratchpad_size function.

Output Parameters

a: Overwritten by the upper or lower triangle of the inverse of A. Specified by uplo.

Exceptions

Exception	Description
`mkl::lapack::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 = -i`, the `i`-th parameter had an illegal value. If `info = i`, the `i`-th diagonal element of the Cholesky factor (and therefore the factor itself) is zero, and the inversion could not be completed. If `info` is equal to the value passed as scratchpad size, and detail() returns non zero, then the passed scratchpad has an insufficient size, and the required size should not be less than the value returned by the detail() method of the exception object.

Exception

Description

mkl::lapack::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 = -i, the i-th parameter had an illegal value.

If info = i, the i-th diagonal element of the Cholesky factor (and therefore the factor itself) is zero, and the inversion could not be completed.

If info is equal to the value passed as scratchpad size, and detail() returns non zero, then the passed scratchpad has an insufficient size, and the required size should not be less than the value returned by the detail() method of the exception object.

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oneMKL - Data Parallel C++ Developer Reference

potri

Description

API