Generates the real orthogonal matrix Q of the QR factorization formed by the geqrf (USM Version) function. This routine belongs to the mkl::lapack namespace.
cl::sycl::event orgqr(cl::sycl::queue &queue, std::int64_t m, std::int64_t n, std::int64_t k, T *a, std::int64_t lda, T *tau, T *scratchpad, std::int64_t scratchpad_size, const cl::sycl::vector_class<cl::sycl::event> &events = {});
orgqr (USM version) supports the following precisions and devices:
T | Devices supported |
---|---|
float | Host, CPU, and GPU |
double | Host, CPU, and GPU |
The routine generates the whole or part of m-by-m orthogonal matrix Q of the QR factorization formed by the routine geqrf (USM Version) function.
Usually Q is determined from the QR factorization of an m by p matrix A with m≥p. To compute the whole matrix Q, use:
mkl::orgqr(queue, m, m, p, a, lda, tau, ...)
To compute the leading p columns of Q (which form an orthonormal basis in the space spanned by the columns of A):
mkl::orgqr(queue, m, p, p, a, lda, tau, ...)
To compute the matrix Qk of the QR factorization of leading k columns of the matrix A:
mkl::orgqr(queue, m, m, k, a, lda, tau, ...)
To compute the leading k columns of Qk (which form an orthonormal basis in the space spanned by leading k columns of the matrix A):
mkl::orgqr(queue, m, k, k, a, lda, tau, ...)
Device queue where calculations will be performed.
The number of rows in the matrix A (0≤m).
The number of columns in the matrix A (0≤n).
The number of elementary reflectors whose product defines the matrix Q (0≤k≤n).
Pointer to the result of geqrf (USM Version).
The leading dimension of a (lda≤m).
Pointer to the result of geqrf (USM Version).
Pointer to scratchpad memory to be used by the routine for storing intermediate results.
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 orgqr_scratchpad_size function.
List of events to wait for before starting computation. Defaults to empty list.
Overwritten by n leading columns of the m-by-m orthogonal matrix Q.
Exceptions
mkl::lapack::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 = -i, the i-th parameter had an illegal value. If info = i, dii is 0. The factorization has been completed, but D is exactly singular. Division by 0 will occur if you use D for solving a system of linear equations. If info is equal to the value passed as scratchpad size, and detail() returns non-zero, then the passed scratchpad has an insufficient size, and the required size should not be less than the value returned by the detail() method of the exception object. |
Output event to wait on to ensure computation is complete.