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syevx_scratchpad_size
Computes size of scratchpad memory required for syevx (USM Version) function. This routine belongs to the oneapi::mkl::lapack namespace.
Description
Computes the number of elements of type T the scratchpad memory to be passed to the syevx (buffer or USM version) function must be able to hold.
API
Syntax
namespace oneapi::mkl::lapack {
template<typename T>
int64_t syevx_scratchpad_size(sycl::queue &queue,
mkl::job jobz,
mkl::rangev range,
mkl::uplo uplo,
int64_t n,
int64_t lda,
T vl,
T vu,
int64_t il,
int64_t iu,
T abstol,
int64_t ldz)
}Input Parameters
- queue
-
Device queue where calculations by the syevx (buffer or USM version) function will be performed.
- jobz
-
Must be job::novec or job::vec.
If jobz = job::novec, then only eigenvalues are computed.
If jobz = job::vec, then eigenvalues and eigenvectors are computed.
- range
-
Must be rangev::all, rangev::values or rangev::indices.
If range = rangev::all, then all the eigenvalues and eigenvectors (if requested by jobz parameters) are computed.
If range = rangev::values, then eigenvalues in the interval (vl, vu] and corresponding eigenvectors (if requested by jobz parameters) are computed.
If range = rangev::indices, then the il-th through iu-th eigenvalues and corresponding eigenvectors (if requested by jobz parameters) are computed.
- uplo
-
Must be uplo::upper or uplo::lower.
If uplo = uplo::upper, a stores the upper triangular part of A.
If uplo = uplo::lower, a stores the lower triangular part of A.
- n
-
The order of the matrix A (0 ≤ n).
- lda
-
The leading dimension of a. Must be at least max(1,n).
- vl
-
If range = rangev::values, the lower bound of the interval to be searched for eigenvalues. vl must be less than vu. Not referenced if range = rangev::all or range = rangev::indices.
- vu
-
If range = rangev::values, the upper bound of the interval to be searched for eigenvalues. vl must be less than vu. Not referenced if range = rangev::all or range = rangev::indices.
- il
-
If range = rangev::indices, the one-based index of the smallest eigenvalue to be returned. Must be 1 ≤ il ≤ iu ≤ n if n > 0 and il = 1 and iu = 0 if n = 0. Not referenced if range = rangev::all or range = rangev::values.
- iu
-
If range = rangev::indices, the one-based index of the largest eigenvalue to be returned. Must be 1 ≤ il ≤ iu ≤ n if n > 0 and il = 1 and iu = 0 if n = 0. Not referenced if range = rangev::all or range = rangev::values.
- abstol
-
The absolute error tolerance for the eigenvalues. An approximate eigenvalue is accepted as converged when it is determined to lie in an interval [a,b] of width less than or equal to abstol + eps * max( |a|,|b| ), where eps is the machine precision. If abstol is less than or equal to zero, then eps*|T| will be used in its place, where |T| is the 1-norm of the tridiagonal matrix obtained by reducing A to tridiagonal form.
- ldz
-
The leading dimension of z. Must be at least max(1,n).
Exceptions
Exception |
Description |
|---|---|
mkl::lapack::exception |
This exception is thrown when an incorrect argument value is supplied. You can determine the position of the incorrect argument by the info() method of the exception object. |
Return Values
The number of elements of type T the scratchpad memory to be passed to the syevx (buffer or USM version) function must be able to hold.