orgtr (USM Version)#
Generates the real orthogonal matrix Q determined by the sytrd (USM
Version) function. This routine belongs to the oneapi::mkl::lapack namespace.
Description#
The routine explicitly generates the n-by-n orthogonal matrix
Q formed by sytrd (USM Version) when
reducing a real symmetric matrix A to tridiagonal form:
A = Q*T*QT. Use this routine after a call to sytrd (USM Version).
API#
Syntax#
namespace oneapi::mkl::lapack {
sycl::event orgtr(sycl::queue &queue,
mkl::uplo uplo,
int64_t n,
T *a,
int64_t lda,
const T *tau,
T *scratchpad,
int64_t scratchpad_size,
const std::vector<sycl::event> &events = {})
}
orgtr (USM version) supports the following precision and
devices.
T |
Devices Supported |
|---|---|
|
CPU |
|
CPU |
Input Parameters#
- queue
Device queue where calculations will be performed.
- uplo
Must be uplo::upper or uplo::lower. Uses the same uplo as supplied to the sytrd (USM Version) function
- n
The order of matrix
Q(0 ≤ n).- a
The pointer
areturned by the sytrd (USM Version) function. The size ofamust be at leastlda*n.- tau
The pointer to
taureturned by the geqrf (USM Version) function.- lda
The leading dimension of
a(lda ≥ n).- scratchpad
Pointer to scratchpad memory to be used by the 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 the orgtr_scratchpad_size function.- events
List of events to wait for before starting computation. Defaults to empty list.
Output Parameters#
- a
Overwritten by the orthogonal matrix
Q.
Exceptions#
Exception |
Description |
|---|---|
|
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 If |
Return Values#
Output event to wait on to ensure computation is complete.