Computes size of scratchpad memory required for ungbr function.

Description

ungbr_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 ungbr function should be able to hold. Calls to this routine must specify the template parameter explicitly.

Syntax

namespace oneapi::mkl::lapack {
template <typename T>
std::int64_t ungbr_scratchpad_size(sycl::queue &queue, oneapi::mkl::generate gen, std::int64_t m, std::int64_t n, std::int64_t k, std::int64_t lda, std::int64_t &scratchpad_size)
}


Input Parameters

queue

Device queue where calculations by ungbr function will be performed.

gen

Must be generate::q or generate::p.

If gen = generate::q, the routine generates the matrix $$Q$$.

If gen = generate::p, the routine generates the matrix $$P^{T}$$.

m

The number of rows in the matrix $$Q$$ or $$P^{T}$$ to be returned $$(0 \le m)$$.

If gen = generate::q, $$m \ge n \ge \min(m, k)$$.

If gen = generate::p, $$n \ge m \ge \min(n, k)$$.

n

The number of columns in the matrix $$Q$$ or $$P^{T}$$ to be returned $$(0 \le n)$$. See m for constraints.

k

If gen = generate::q, the number of columns in the original $$m \times k$$ matrix reduced by gebrd.

If gen = generate::p, the number of rows in the original $$k \times n$$ matrix reduced by gebrd.

lda

The leading dimension of a.

Return Value

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