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apache--tvm/python/tvm/topi/signal.py
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chore: import upstream snapshot with attribution
2026-07-13 13:36:25 +08:00

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7.5 KiB
Python

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