getrs (USM Version)#
Solves a system of linear equations with an LU-factored square
coefficient matrix, with multiple right-hand sides. This routine belongs
to the oneapi::mkl::lapack namespace.
Description#
The routine solves for X the following systems of linear
equations:
Equation |
Condition |
|---|---|
|
if |
|
if |
|
if |
Before calling this routine, you must call the getrf (USM Version) function to compute the LU factorization of A.
API#
Syntax#
namespace oneapi::mkl::lapack {
sycl::event getrs(sycl::queue &queue,
mkl::transpose trans,
int64_t n,
int64_t nrhs,
const T *a,
int64_t lda,
const int64_t *ipiv,
T *b,
int64_t ldb,
T *scratchpad,
int64_t scratchpad_size,
const std::vector<sycl::event> &events = {})
}
getrs (USM version) supports the following precisions and
devices:
T |
Devices supported |
|---|---|
|
CPU, GPU |
|
CPU, GPU |
|
CPU, GPU |
|
CPU, GPU |
Input Parameters#
- queue
Device queue where calculations will be performed.
- trans
Indicates the form of the equations:
If
trans=mkl::transpose::nontrans, thenA*X = Bis solved forX.If
trans=mkl::transpose::trans, thenAT*X = Bis solved forX.If
trans=mkl::transpose::conjtrans, thenAH*X = Bis solved forX.- n
The order of the matrix
Aand the number of rows in matrixB(0 ≤ n).- nrhs
The number of right-hand sides (
0 ≤ nrhs).- a
Pointer to the array containing the factorization of the matrix
A, as returned by getrf (USM Version). The size of the array must be at leastlda*n.- lda
The leading dimension of a.
- ipiv
Array, size at least
max(1, n). The ipiv array, as returned by getrf (USM Version).- b
The array b contains the matrix
Bwhose columns are the right-hand sides for the systems of equations. The size of b must be at leastldb*nrhs.- ldb
The leading dimension of b.
- 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 getrs_scratchpad_size function.- events
List of events to wait for before starting computation. Defaults to empty list.
Output Parameters#
- b
The array b is overwritten by the solution matrix
X.
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.