215 lines
7.5 KiB
Python
215 lines
7.5 KiB
Python
# Licensed to the Apache Software Foundation (ASF) under one
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# or more contributor license agreements. See the NOTICE file
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# distributed with this work for additional information
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# regarding copyright ownership. The ASF licenses this file
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# to you under the Apache License, Version 2.0 (the
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# "License"); you may not use this file except in compliance
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# with the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing,
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# software distributed under the License is distributed on an
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# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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# KIND, either express or implied. See the License for the
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# specific language governing permissions and limitations
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# under the License.
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# pylint: disable=invalid-name, too-many-arguments, too-many-nested-blocks, unused-argument
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"""STFT operator"""
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from math import pi
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from tvm import te, tirx
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from tvm.script.ir_builder import IRBuilder
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from tvm.script.ir_builder import tirx as T
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def stft(
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data,
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n_fft,
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hop_length,
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win_length,
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window,
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normalized,
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onesided,
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output_shape,
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):
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"""
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The STFT computes the Fourier transform of short overlapping windows of the input.
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This gives frequency components of the signal as they change over time.
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Parameters
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----------
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data : te.Tensor
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Either a 1-D tensor or a 2-D batch tensor.
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n_fft : int
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The size of Fourier transform
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hop_length : int
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The distance between neighboring sliding window frames
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win_length : int
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The size of window frame and STFT filter
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window : te.Tensor
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A 1-D tensor window frame
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normalized : bool
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Whether to return the normalized STFT results
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onesided : bool
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Whether to return onesided result or fill with conjugate symmetry
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Returns
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-------
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output : te.Tensor
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Tensor containing the STFT result
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Examples
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--------
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.. code-block:: python
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data = [1, 2, 3, 4, 5, 6]
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window = [4, 3, 2]
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[n_fft, hop_length, win_length, normalized, onesided] = [3, 3, 3, False, True]
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topi.stft(data, n_fft, hop_length, win_length, window, normalized, onesided)
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-> [[[15.0000, 0.0000], [34.0000, 0.0000]], [[ 4.5000, 0.8660], [ 1.0000, -1.7321]]]
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"""
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def gen_ir(
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data_ptr,
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n_fft,
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hop_length,
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win_length,
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window_ptr,
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normalized,
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onesided,
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output_ptr,
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loop_kind,
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):
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col_loop = T.vectorized if loop_kind == "vectorize" else T.serial
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with IRBuilder() as ib:
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data = T.buffer_proxy(data_ptr)
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window = T.buffer_proxy(window_ptr)
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output = T.buffer_proxy(output_ptr)
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# https://librosa.org/doc/0.7.2/_modules/librosa/core/spectrum.html#stft
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with T.parallel(0, output_ptr.shape[0] * output_ptr.shape[1]) as batch_row:
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with col_loop(0, output_ptr.shape[2]) as col:
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batch = tirx.floordiv(batch_row, output_ptr.shape[1])
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row = tirx.floormod(batch_row, output_ptr.shape[1])
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output[batch, row, col, 0] = tirx.Cast(data_ptr.dtype, 0)
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output[batch, row, col, 1] = tirx.Cast(data_ptr.dtype, 0)
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with T.serial(0, win_length) as wlen:
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output[batch, row, col, 0] += (
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window[wlen]
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* data[batch, col * hop_length + wlen]
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* tirx.cos(2 * pi * row * wlen / win_length)
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)
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output[batch, row, col, 1] -= (
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window[wlen]
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* data[batch, col * hop_length + wlen]
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* tirx.sin(2 * pi * row * wlen / win_length)
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)
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with T.If(normalized):
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with T.Then():
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output[batch, row, col, 0] /= tirx.sqrt(tirx.const(n_fft, "float32"))
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output[batch, row, col, 1] /= tirx.sqrt(tirx.const(n_fft, "float32"))
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return ib.get()
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output_buf = tirx.decl_buffer(output_shape, data.dtype, "output_buf", layout=None)
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loop_kind = "vectorize"
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if isinstance(output_shape[2], tirx.expr.Var): # any_dim
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loop_kind = "serial"
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return te.extern(
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output_shape,
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[data, window],
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lambda ins, outs: gen_ir(
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ins[0], n_fft, hop_length, win_length, ins[1], normalized, onesided, outs[0], loop_kind
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),
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dtype=[data.dtype],
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out_buffers=[output_buf],
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name="stft_cpu",
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tag="stft_cpu",
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)
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def dft(
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re_data: te.Tensor,
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im_data: te.Tensor,
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inverse: tirx.IntImm,
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):
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"""
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Computes the discrete Fourier transform of input (calculation along the last axis).
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This gives frequency components of the signal as they change over time.
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Parameters
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----------
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re_data : te.Tensor
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N-D tensor, real part of the input signal.
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im_data : te.Tensor
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N-D tensor, imaginary part of the input signal.
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If the signal is real, then the values of this tensor are zeros.
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inverse : bool
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Whether to perform the inverse discrete fourier transform.
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Returns
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-------
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re_output : te.Tensor
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The Fourier Transform of the input (Real part).
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im_output : te.Tensor
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The Fourier Transform of the input (Imaginary part).
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"""
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def gen_ir(
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re_data_buf,
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im_data_buf,
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re_output_buf,
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im_output_buf,
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):
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with IRBuilder() as ib:
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re_data_ptr = T.buffer_proxy(re_data_buf)
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im_data_ptr = T.buffer_proxy(im_data_buf)
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re_output_ptr = T.buffer_proxy(re_output_buf)
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im_output_ptr = T.buffer_proxy(im_output_buf)
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shape = re_data.shape
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n_fft = shape[len(shape) - 1]
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base_range = 1
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for i in range(len(shape) - 1):
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base_range *= shape[i]
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sign = -1 if inverse else 1
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factor = 1.0 / n_fft if inverse else 1.0
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with T.parallel(0, base_range) as i:
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base_idx = i * n_fft
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with T.serial(0, n_fft) as n:
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n_idx = base_idx + n
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re_output_ptr[n_idx] = tirx.Cast(re_output_ptr.dtype, 0)
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im_output_ptr[n_idx] = tirx.Cast(im_output_ptr.dtype, 0)
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_w = sign * -2 * pi * n / n_fft
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with T.serial(0, n_fft) as k:
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k_idx = base_idx + k
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w = _w * k
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cos_w = tirx.Cast(re_output_ptr.dtype, tirx.cos(w))
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sin_w = tirx.Cast(re_output_ptr.dtype, tirx.sin(w))
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re_output_ptr[n_idx] += (
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re_data_ptr[k_idx] * cos_w - im_data_ptr[k_idx] * sin_w
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)
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im_output_ptr[n_idx] += (
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re_data_ptr[k_idx] * sin_w + im_data_ptr[k_idx] * cos_w
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)
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re_output_ptr[n_idx] *= tirx.Cast(re_output_ptr.dtype, factor)
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im_output_ptr[n_idx] *= tirx.Cast(im_output_ptr.dtype, factor)
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return ib.get()
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output_shape = [re_data.shape] * 2
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return te.extern(
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shape=output_shape,
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inputs=[re_data, im_data],
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fcompute=lambda ins, outs: gen_ir(ins[0], ins[1], outs[0], outs[1]),
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dtype=[re_data.dtype, im_data.dtype],
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name="dft_cpu",
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tag="dft_cpu",
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)
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