Generates the complex unitary matrix Q determined by the hetrd (USM Version) function. This routine belongs to the mkl::lapack namespace.
cl::sycl::event ungtr(cl::sycl::queue &queue, mkl::uplo uplo, std::int64_t n, T *a, std::int64_t lda, T *tau, T *tau, T *scratchpad, std::int64_t scratchpad_size, const cl::sycl::vector_class<cl::sycl::event> &events = {});
ungtr (USM version) supports the following precision and devices.
T | Devices Supported |
---|---|
float | Host and CPU |
double | Host and CPU |
The routine explicitly generates the n-by-n unitary matrix Q formed by the hetrd (USM Version) function when reducing a complex Hermitian matrix A to tridiagonal form: A = Q*T*QT. Use this routine after a call to hetrd (USM Version) function.
Device queue where calculations will be performed.
Must be uplo::upper or uplo::lower. Uses the same uplo as supplied to the hetrd (USM Version) function.
The order of matrix Q (0≤n).
The pointer a returned by the hetrd (USM Version) function. The second dimension of a must be at least max(1, n).
The leading dimension of a (n≤lda).
The pointer tau returned by the hetrd (USM Version) function. The dimension of tau must be at least max(1,n-1).
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 ungtr_scratchpad_size function.
List of events to wait for before starting computation. Defaults to empty list.
Overwritten by the unitary 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 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.