potri¶

Computes the inverse of a symmetric (Hermitian) positive-definite matrix using the Cholesky factorization.

potri supports the following precisions.

T

float

double

std::complex<float>

std::complex<double>

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.

potri (BUFFER Version)¶

Syntax

void onemkl::lapack::potri(cl::sycl::queue &queue, onemkl::uplo upper_lower, std::int64_t n, cl::sycl::buffer<T, 1> &a, std::int64_t lda, cl::sycl::buffer<T, 1> &scratchpad, std::int64_t scratchpad_size)¶

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

Indicates how the input matrix A has been factored:

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

If upper_lower = onemkl::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. The second dimension of a must be at least max(1, n).

lda

The leading dimension of a.

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 potri_scratchpad_size function.

Output Parameters

a: Overwritten by the upper or lower triangle of the inverse of A. Specified by upper_lower.
scratchpad: Buffer holding scratchpad memory to be used by routine for storing intermediate results.

Throws

onemkl::lapack::exception

Exception is thrown in case of problems happened during calculations. The info code of the problem can be obtained by get_info() method of 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 equals to value passed as scratchpad size, and get_detail() returns non zero, then passed scratchpad is of insufficient size, and required size should not be less than value return by get_detail() method of exception object.

potri (USM Version)¶