compute_backward<typename descriptor_type, typename_data_type>¶
Computes the backward FFT. This routine belongs to the oneapi::mkl::dft
namespace.
Syntax
Using SYCL buffers
namespace oneapi::mkl::dft{
void compute_backward<descriptor_type,
data_type>(descriptor_type &desc, cl::sycl::buffer<data_type,
1> &inout);
void compute_backward<descriptor_type, input_type,
output_type>(descriptor_type &desc,
cl::sycl::buffer<input_type, 1> &in,
cl::sycl::buffer<output_type, 1> &out);
}
Using USM pointers
namespace oneapi::mkl::dft{
cl::sycl::event compute_backward<descriptor_type,
data_type>(descriptor_type &desc, data_type* inout, const
cl::sycl::vector_class<cl::sycl::event> &dependencies = {});
cl::sycl::event compute_backward<descriptor_type, input_type,
output_type>(descriptor_type &desc, input_type* in,
output_type* out, const
cl::sycl::vector_class<cl::sycl::event> &dependencies = {});
}
Include Files
oneapi/mkl/dfti.hpp
Description
The compute_backward<typename descriptor_type, typename_data_type>
function accepts a descriptor object followed by one or more data
parameters. Given a successfully configured and committed descriptor,
this function computes the backward FFT, that is, the
transform
with the minus sign in the exponent, δ = +1. This function throws an
std::runtime_exception
in the case that it fails.
The FFT descriptor must be properly configured prior to the function call. Function calls needed to configure an FFT descriptor for a particular call to an FFT computation function are summarized in Configuring and Computing an FFT in C/C++.
The number of the data parameters that the function requires may vary depending on the configuration of the descriptor. This variation is accommodated by variable parameters.
Input Parameters
Name |
Type |
Description |
---|---|---|
inout, in |
|
SYCL buffer or USM pointer containing an array of length no less than specified at during construction of the handle. |
The suffix in parameter names corresponds to the value of the
configuration parameter mkl::dft::ConfigParam::PLACEMENT
as follows:
inout to INPLACE
in to NOT_INPLACE
Output Parameters
Name |
Type |
Description |
---|---|---|
inout, out |
|
SYCL buffer or USM pointer containing an array of length no less than specified during construction of the handle. |
The suffix in parameter names corresponds to the value of the
configuration parameter mkl::dft::config_param::PLACEMENT
as follows:
inout to INPLACE
out to NOT_INPLACE