# getri#

Computes the inverse of an LU-factored general matrix determined by getrf.

Description

getri supports the following precisions.

T

float

double

std::complex<float>

std::complex<double>

The routine computes the inverse $$A^{-1}$$ of a general matrix $$A$$. Before calling this routine, call getrf to factorize $$A$$.

## getri (BUFFER Version)#

Syntax

namespace oneapi::mkl::lapack {
void getri(cl::sycl::queue &queue, std::int64_t n, cl::sycl::buffer<T,1> &a, std::int64_t lda, cl::sycl::buffer<std::int64_t,1> &ipiv, cl::sycl::buffer<T,1> &scratchpad, std::int64_t scratchpad_size)
}


Input Parameters

queue

The queue where the routine should be executed.

n

The order of the matrix $$A$$ $$(0 \le n)$$.

a

The buffer a as returned by getrf. Must be of size at least $$\text{lda} \cdot \max(1,n)$$.

lda

The leading dimension of a $$(n \le \text{lda})$$.

ipiv

The buffer as returned by getrf. The dimension of ipiv must be at least $$\max(1, n)$$.

Size of scratchpad memory as a number of floating point elements of type T. Size should not be less than the value returned by getri_scratchpad_size function.

Output Parameters

a

Overwritten by the $$n \times n$$ matrix $$A$$.

Buffer holding scratchpad memory to be used by routine for storing intermediate results.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::mkl::unimplemented

oneapi::mkl::unsupported_device

oneapi::mkl::lapack::invalid_argument

oneapi::mkl::lapack::computation_error

Exception is thrown in case of problems during calculations. The info code of the problem can be obtained by info() method of exception object:

If $$\text{info}=-i$$, the $$i$$-th parameter had an illegal value.

If $$\text{info}$$ equals to value passed as scratchpad size, and detail() returns non zero, then passed scratchpad is of insufficient size, and required size should not be less than value return by detail() method of exception object.

## getri (USM Version)#

Syntax

namespace oneapi::mkl::lapack {
cl::sycl::event getri(cl::sycl::queue &queue, std::int64_t n, T *a, std::int64_t lda, std::int64_t *ipiv, T *scratchpad, std::int64_t scratchpad_size, const std::vector<cl::sycl::event> &events = {})
}


Input Parameters

queue

The queue where the routine should be executed.

n

The order of the matrix $$A$$ $$(0 \le n)$$.

a

The array as returned by getrf. Must be of size at least $$\text{lda} \cdot \max(1,n)$$.

lda

The leading dimension of a $$(n \le \text{lda})$$.

ipiv

The array as returned by getrf. The dimension of ipiv must be at least $$\max(1, n)$$.

Size of scratchpad memory as a number of floating point elements of type T. Size should not be less than the value returned by getri_scratchpad_size function.

events

List of events to wait for before starting computation. Defaults to empty list.

Output Parameters

a

Overwritten by the $$n \times n$$ matrix $$A$$.

Pointer to scratchpad memory to be used by routine for storing intermediate results.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::mkl::unimplemented

oneapi::mkl::unsupported_device

oneapi::mkl::lapack::invalid_argument

oneapi::mkl::lapack::computation_error

Exception is thrown in case of problems during calculations. The info code of the problem can be obtained by info() method of exception object:

If $$\text{info}=-i$$, the $$i$$-th parameter had an illegal value.

If $$\text{info}$$ equals to value passed as scratchpad size, and detail() returns non zero, then passed scratchpad is of insufficient size, and required size should not be less than value return by detail() method of exception object.

Return Values

Output event to wait on to ensure computation is complete.

Parent topic: LAPACK Linear Equation Routines