orgqr_batch (Buffer Strided Version)

oneMKL - Data Parallel C++ Developer Reference

Download PDF

ID 772045

Date 6/24/2024

Version

Public

A newer version of this document is available. Customers should click here to go to the newest version.

Visible to Intel only — GUID: GUID-4227FCD7-F83F-4B00-B266-61275F1EBD07

View Details

orgqr_batch (Buffer Strided Version)

Generates the real orthogonal matrices Q_i of the batch QR factorizations formed by geqrf_batch (Buffer Strided Version). This routine belongs to the oneapi::mkl::lapack namespace.

Description
API

Description

The routine generates the wholes or parts of the orthogonal matrices Q_i of the batch of QR factorizations formed by the routine geqrf_batch (Buffer Strided Version). Usually, Q_i is determined from the QR factorization of an m-by-p matrix A_i with m ≥ p.

To compute the whole matrices Q_i, use:

orgqr_batch(queue, m, m, p, a, ...)

To compute the leading p columns of Q_i (which form an orthonormal basis in the space spanned by the columns of A_i):

orgqr_batch(queue, m, p, p, a, ...)

To compute the matrices Q_i^k of the QR factorizations of leading k columns of the matrices A_i:

orgqr_batch(queue, m, m, k, a, ...)

To compute the leading k columns of Q_i^k (which form an orthonormal basis in the space spanned by leading k columns of the matrices A_i):

orgqr_batch(queue, m, k, k, a, ...)

API

Syntax

namespace oneapi::mkl::lapack {
  void orgqr_batch(sycl::queue &queue,
  std::int64_t m,
  std::int64_t n,
  std::int64_t k,
  sycl::buffer<T> &a,
  std::int64_t lda,
  std::int64_t stride_a,
  sycl::buffer<T> &tau,
  std::int64_t stride_tau,
  std::int64_t batch_size,
  sycl::buffer<T> &scratchpad,
  std::int64_t scratchpad_size)
}

This function supports the following precisions and devices:

T	Devices supported
`float`	CPU and GPU*
`double`	CPU and GPU*

*Interface support only; all computations are performed on the CPU.

Input Parameters

queue: Device queue where calculations will be performed.
m: The number of rows in the matrices A_i (m ≥ 0).
n: The number of columns in the matrices A_i (n ≥ 0).
k: the number of elementary reflectors whose product defines the matrices Q_i (0 ≤ k ≤ n) .
a: Array resulting after a call to geqrf_batch (Buffer Strided Version).
lda: The leading dimension of A_i (lda ≥ max(1,m)).
stride_a: The stride between the beginnings of matrices A_i inside the batch array a (stride_a ≥ max(1, lda * n)).
tau: Array resulting after a call to geqrf_batch (Buffer Strided Version).
stride_tau: The stride between the beginnings of arrays tau_i inside the array tau (stride_tau ≥ max(1, min(m,n))).
batch_size: The number of problems in a batch (batch_size ≥ 0).
scratchpad: Scratchpad memory to be used by 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 orgqr_batch_scratchpad_size (Strided Version).

Output Parameters

a: Array data is overwritten by a batch of n leading columns of the m-by-m orthogonal matrices Q_i.

Exceptions

Exception	Description
`mkl::lapack::batch_exception`	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 `info = -n`, the `n`-th parameter had an illegal value. If `info` equals the value passed as scratchpad size, and detail() returns non-zero, then the passed scratchpad is of insufficient size, and the required size should be not less then value returned by the detail() method of the exception object.

Exception

Description

mkl::lapack::batch_exception

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 info = -n, the n-th parameter had an illegal value.

If info equals the value passed as scratchpad size, and detail() returns non-zero, then the passed scratchpad is of insufficient size, and the required size should be not less then value returned by the detail() method of the exception object.

Select Your Language

Using Intel.com Search

Quick Links

Recent Searches

Advanced Search

Only search in

oneMKL - Data Parallel C++ Developer Reference

orgqr_batch (Buffer Strided Version)

Description

API