Developer Reference

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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

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(cl::sycl::queue &queue, mkl::uplo uplo, std::int64_t n, cl::sycl::buffer<T> &a, std::int64_t lda, cl::sycl::buffer<T> &scratchpad, std::int64_t scratchpad_size) }
potri
supports the following precisions and devices:
T
Devices Supported
float
Host, CPU, and GPU
double
Host, CPU, and GPU
std::complex<float>
Host, CPU, and GPU
std::complex<double>
Host, 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.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.