ungtr
Generates the complex unitary matrix Q determined by
hetrd. This routine belongs to the
oneapi::mkl::lapack
namespace.API
Syntax
namespace oneapi::mkl::lapack {
void ungtr(cl::sycl::queue &queue,
mkl::uplo uplo,
std::int64_t n,
cl::sycl::buffer<T> &a,
std::int64_t lda,
cl::sycl::buffer<T> &tau,
cl::sycl::buffer<T> &scratchpad,
std::int64_t scratchpad_size)
}
ungtr
supports the following precision and devices.T | Devices Supported |
---|---|
std::complex<float> | Host and CPU |
std::complex<double> | Host and 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 hetrd function.
- n
- The order of matrixQ(0≤n).
- a
- lda
- The leading dimension ofa(n≤lda).
- tau
- The buffer tau returned by the hetrd function. The dimension of tau must be at leastmax(1,n-1).
- scratchpad
- Buffer holding 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 typeT. Size should not be less than the value returned by the ungtr_scratchpad_size function.
Output Parameters
- a
- Overwritten by the unitary matrixQ.
Exceptions
Exception | Description |
---|---|
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. |