Source code for jax._src.lax.other

# Copyright 2020 Google LLC
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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# distributed under the License is distributed on an "AS IS" BASIS,
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from typing import Any, Optional, Sequence, Tuple, Union
from jax._src.numpy import lax_numpy as jnp
from jax._src.util import prod
from . import lax

DType = Any

[docs]def conv_general_dilated_patches( lhs: lax.Array, filter_shape: Sequence[int], window_strides: Sequence[int], padding: Union[str, Sequence[Tuple[int, int]]], lhs_dilation: Sequence[int] = None, rhs_dilation: Sequence[int] = None, dimension_numbers: lax.ConvGeneralDilatedDimensionNumbers = None, precision: lax.PrecisionType = None, preferred_element_type: Optional[DType] = None, ) -> lax.Array: """Extract patches subject to the receptive field of `conv_general_dilated`. Runs the input through a convolution with given parameters. The kernel of the convolution is constructed such that the output channel dimension `"C"` contains flattened image patches, so instead a single `"C"` dimension represents, for example, three dimensions `"chw"` collapsed. The order of these dimensions is `"c" + ''.join(c for c in rhs_spec if c not in 'OI')`, where `rhs_spec == dimension_numbers[1]`, and the size of this `"C"` dimension is therefore the size of each patch, i.e. ` * lhs.shape[lhs_spec.index('C')]`, where `lhs_spec == dimension_numbers[0]`. Docstring below adapted from `jax.lax.conv_general_dilated`. See Also: Args: lhs: a rank `n+2` dimensional input array. filter_shape: a sequence of `n` integers, representing the receptive window spatial shape in the order as specified in `rhs_spec = dimension_numbers[1]`. window_strides: a sequence of `n` integers, representing the inter-window strides. padding: either the string `'SAME'`, the string `'VALID'`, or a sequence of `n` `(low, high)` integer pairs that give the padding to apply before and after each spatial dimension. lhs_dilation: `None`, or a sequence of `n` integers, giving the dilation factor to apply in each spatial dimension of `lhs`. LHS dilation is also known as transposed convolution. rhs_dilation: `None`, or a sequence of `n` integers, giving the dilation factor to apply in each spatial dimension of `rhs`. RHS dilation is also known as atrous convolution. dimension_numbers: either `None`, or a 3-tuple `(lhs_spec, rhs_spec, out_spec)`, where each element is a string of length `n+2`. `None` defaults to `("NCHWD..., OIHWD..., NCHWD...")`. precision: Optional. Either ``None``, which means the default precision for the backend, or a ``lax.Precision`` enum value (``Precision.DEFAULT``, ``Precision.HIGH`` or ``Precision.HIGHEST``). preferred_element_type: Optional. Either ``None``, which means the default accumulation type for the input types, or a datatype, indicating to accumulate results to and return a result with that datatype. Returns: A rank `n+2` array containing the flattened image patches in the output channel (`"C"`) dimension. For example if `dimension_numbers = ("NcHW", "OIwh", "CNHW")`, the output has dimension numbers `"CNHW" = "{cwh}NHW"`, with the size of dimension `"C"` equal to the size of each patch (` * lhs.shape[lhs_spec.index('C')]`). """ filter_shape = tuple(filter_shape) dimension_numbers = lax.conv_dimension_numbers( lhs.shape, (1, 1) + filter_shape, dimension_numbers) lhs_spec, rhs_spec, out_spec = dimension_numbers spatial_size = prod(filter_shape) n_channels = lhs.shape[lhs_spec[1]] # Move separate `lhs` spatial locations into separate `rhs` channels. rhs = jnp.eye(spatial_size, dtype=lhs.dtype).reshape(filter_shape * 2) rhs = rhs.reshape((spatial_size, 1) + filter_shape) rhs = jnp.tile(rhs, (n_channels,) + (1,) * (rhs.ndim - 1)) rhs = jnp.moveaxis(rhs, (0, 1), (rhs_spec[0], rhs_spec[1])) out = lax.conv_general_dilated( lhs=lhs, rhs=rhs, window_strides=window_strides, padding=padding, lhs_dilation=lhs_dilation, rhs_dilation=rhs_dilation, dimension_numbers=dimension_numbers, precision=None if precision is None else (precision, lax.Precision.DEFAULT), feature_group_count=n_channels, preferred_element_type=preferred_element_type ) return out