hegvd_scratchpad_size#

Computes size of scratchpad memory required for hegvd function.

Description

hegvd_scratchpad_size supports the following precisions.

T

std::complex<float>

std::complex<double>

Computes the number of elements of type T the scratchpad memory to be passed to hegvd function should be able to hold. Calls to this routine must specify the template parameter explicitly.

hegvd_scratchpad_size#

Syntax

namespace oneapi::mkl::lapack {
  template <typename T>
  std::int64_t hegvd_scratchpad_size(cl::sycl::queue &queue, std::int64_t itype, oneapi::mkl::job jobz, oneapi::mkl::uplo upper_lower, std::int64_t n, std::int64_t lda, std::int64_t ldb)
}

Input Parameters

queue

Device queue where calculations by hegvd function will be performed.

itype

Must be 1 or 2 or 3. Specifies the problem type to be solved:

if \(\text{itype} = 1\), the problem type is \(Ax = \lambda Bx\);

if \(\text{itype} = 2\), the problem type is \(ABx = \lambda x\);

if \(\text{itype} = 3\), the problem type is \(BAx = \lambda x\).

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.

upper_lower

Must be uplo::upper or uplo::lower.

If upper_lower = uplo::upper, a and b store the upper triangular part of \(A\) and \(B\).

If upper_lower = uplo::lower, a and b store the lower triangular part of \(A\) and \(B\).

n

The order of the matrices \(A\) and \(B\) (\(0 \le n\)).

lda

The leading dimension of a. Currently lda is not referenced in this function.

ldb

The leading dimension of b. Currently ldb is not referenced in this function.

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

Exception is thrown in case of incorrect supplied argument value. Position of wrong argument can be determined by info() method of exception object.

Return Value

The number of elements of type T the scratchpad memory to be passed to hegvd function should be able to hold.

Parent topic: LAPACK Singular Value and Eigenvalue Problem Routines