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Pull Request — master (#353)
by Fernando
01:11
created

torchio.transforms.transform.Transform.to_range()   A

Complexity

Conditions 2

Size

Total Lines 6
Code Lines 5

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 2
eloc 5
nop 2
dl 0
loc 6
rs 10
c 0
b 0
f 0
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import copy
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import numbers
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from abc import ABC, abstractmethod
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from contextlib import contextmanager
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from typing import Optional, Union, Tuple, Sequence
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import torch
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import numpy as np
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import SimpleITK as sitk
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from ..data.subject import Subject
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from .. import TypeData, DATA, TypeNumber
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from ..utils import nib_to_sitk, sitk_to_nib, to_tuple
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from .interpolation import Interpolation, get_sitk_interpolator
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from .data_parser import DataParser, TypeTransformInput
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class Transform(ABC):
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    """Abstract class for all TorchIO transforms.
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    All subclasses should overwrite
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    :py:meth:`torchio.tranforms.Transform.apply_transform`,
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    which takes data, applies some transformation and returns the result.
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    The input can be an instance of
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    :py:class:`torchio.Subject`,
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    :py:class:`torchio.Image`,
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    :py:class:`numpy.ndarray`,
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    :py:class:`torch.Tensor`,
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    :py:class:`SimpleITK.image`,
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    or a Python dictionary.
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    Args:
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        p: Probability that this transform will be applied.
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        copy: Make a shallow copy of the input before applying the transform.
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        keys: Mandatory if the input is a Python dictionary. The transform will
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            be applied only to the data in each key.
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    """
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    def __init__(
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            self,
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            p: float = 1,
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            copy: bool = True,
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            keys: Optional[Sequence[str]] = None,
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            ):
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        self.probability = self.parse_probability(p)
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        self.copy = copy
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        self.keys = keys
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    def __call__(
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            self,
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            data: TypeTransformInput,
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            ) -> TypeTransformInput:
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        """Transform data and return a result of the same type.
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        Args:
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            data: Instance of 1) :py:class:`~torchio.Subject`, 4D
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                :py:class:`torch.Tensor` or NumPy array with dimensions
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                :math:`(C, W, H, D)`, where :math:`C` is the number of channels
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                and :math:`W, H, D` are the spatial dimensions. If the input is
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                a tensor, the affine matrix will be set to identity. Other
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                valid input types are a SimpleITK image, a
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                :py:class:`torch.Image`, a NiBabel Nifti1 Image or a Python
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                dictionary. The output type is the same as te input type.
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        """
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        if torch.rand(1).item() > self.probability:
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            return data
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        data_parser = DataParser(data, keys=self.keys)
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        subject = data_parser.get_subject()
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        if self.copy:
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            subject = copy.copy(subject)
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        with np.errstate(all='raise'):
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            transformed = self.apply_transform(subject)
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        self.add_transform_to_subject_history(transformed)
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        for image in transformed.get_images(intensity_only=False):
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            ndim = image[DATA].ndim
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            assert ndim == 4, f'Output of {self.name} is {ndim}D'
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        output = data_parser.get_output(transformed)
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        return output
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    def __repr__(self):
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        if hasattr(self, 'args_names'):
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            names = self.args_names
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            args_strings = [f'{arg}={getattr(self, arg)}' for arg in names]
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            if hasattr(self, 'invert_transform') and self.invert_transform:
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                args_strings.append('invert=True')
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            args_string = ', '.join(args_strings)
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            return f'{self.name}({args_string})'
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        else:
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            return super().__repr__()
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    @property
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    def name(self):
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        return self.__class__.__name__
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    @abstractmethod
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    def apply_transform(self, subject: Subject):
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        raise NotImplementedError
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    def add_transform_to_subject_history(self, subject):
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        from .augmentation import RandomTransform
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        from . import Compose, OneOf, CropOrPad
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        call_others = (
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            RandomTransform,
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            Compose,
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            OneOf,
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            CropOrPad,
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        )
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        if not isinstance(self, call_others):
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            subject.add_transform(self, self.get_arguments())
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    @staticmethod
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    def to_range(n, around):
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        if around is None:
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            return 0, n
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        else:
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            return around - n, around + n
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    def parse_params(self, params, around, name, make_ranges=True, **kwargs):
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        params = to_tuple(params)
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        if len(params) == 1 or (len(params) == 2 and make_ranges):  # d or (a, b)
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            params *= 3  # (d, d, d) or (a, b, a, b, a, b)
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        if len(params) == 3 and make_ranges:  # (a, b, c)
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            items = [self.to_range(n, around) for n in params]
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            # (-a, a, -b, b, -c, c) or (1-a, 1+a, 1-b, 1+b, 1-c, 1+c)
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            params = [n for prange in items for n in prange]
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        if make_ranges:
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            if len(params) != 6:
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                message = (
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                    f'If "{name}" is a sequence, it must have length 2, 3 or 6,'
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                    f' not {len(params)}'
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                )
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                raise ValueError(message)
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            for param_range in zip(params[::2], params[1::2]):
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                self.parse_range(param_range, name, **kwargs)
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        return tuple(params)
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    @staticmethod
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    def parse_range(
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            nums_range: Union[TypeNumber, Tuple[TypeNumber, TypeNumber]],
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            name: str,
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            min_constraint: TypeNumber = None,
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            max_constraint: TypeNumber = None,
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            type_constraint: type = None,
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            ) -> Tuple[TypeNumber, TypeNumber]:
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        r"""Adapted from ``torchvision.transforms.RandomRotation``.
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        Args:
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            nums_range: Tuple of two numbers :math:`(n_{min}, n_{max})`,
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                where :math:`n_{min} \leq n_{max}`.
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                If a single positive number :math:`n` is provided,
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                :math:`n_{min} = -n` and :math:`n_{max} = n`.
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            name: Name of the parameter, so that an informative error message
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                can be printed.
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            min_constraint: Minimal value that :math:`n_{min}` can take,
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                default is None, i.e. there is no minimal value.
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            max_constraint: Maximal value that :math:`n_{max}` can take,
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                default is None, i.e. there is no maximal value.
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            type_constraint: Precise type that :math:`n_{max}` and
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                :math:`n_{min}` must take.
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        Returns:
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            A tuple of two numbers :math:`(n_{min}, n_{max})`.
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        Raises:
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            ValueError: if :attr:`nums_range` is negative
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            ValueError: if :math:`n_{max}` or :math:`n_{min}` is not a number
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            ValueError: if :math:`n_{max} \lt n_{min}`
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            ValueError: if :attr:`min_constraint` is not None and
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                :math:`n_{min}` is smaller than :attr:`min_constraint`
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            ValueError: if :attr:`max_constraint` is not None and
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                :math:`n_{max}` is greater than :attr:`max_constraint`
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            ValueError: if :attr:`type_constraint` is not None and
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                :math:`n_{max}` and :math:`n_{max}` are not of type
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                :attr:`type_constraint`.
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        """
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        if isinstance(nums_range, numbers.Number):  # single number given
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            if nums_range < 0:
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                raise ValueError(
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                    f'If {name} is a single number,'
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                    f' it must be positive, not {nums_range}')
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            if min_constraint is not None and nums_range < min_constraint:
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                raise ValueError(
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                    f'If {name} is a single number, it must be greater'
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                    f' than {min_constraint}, not {nums_range}'
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                )
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            if max_constraint is not None and nums_range > max_constraint:
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                raise ValueError(
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                    f'If {name} is a single number, it must be smaller'
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                    f' than {max_constraint}, not {nums_range}'
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                )
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            if type_constraint is not None:
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                if not isinstance(nums_range, type_constraint):
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                    raise ValueError(
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                        f'If {name} is a single number, it must be of'
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                        f' type {type_constraint}, not {nums_range}'
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                    )
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            min_range = -nums_range if min_constraint is None else nums_range
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            return (min_range, nums_range)
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        try:
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            min_value, max_value = nums_range
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        except (TypeError, ValueError):
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            raise ValueError(
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                f'If {name} is not a single number, it must be'
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                f' a sequence of len 2, not {nums_range}'
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            )
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        min_is_number = isinstance(min_value, numbers.Number)
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        max_is_number = isinstance(max_value, numbers.Number)
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        if not min_is_number or not max_is_number:
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            message = (
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                f'{name} values must be numbers, not {nums_range}')
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            raise ValueError(message)
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        if min_value > max_value:
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            raise ValueError(
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                f'If {name} is a sequence, the second value must be'
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                f' equal or greater than the first, but it is {nums_range}')
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        if min_constraint is not None and min_value < min_constraint:
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            raise ValueError(
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                f'If {name} is a sequence, the first value must be greater'
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                f' than {min_constraint}, but it is {min_value}'
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            )
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        if max_constraint is not None and max_value > max_constraint:
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            raise ValueError(
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                f'If {name} is a sequence, the second value must be smaller'
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                f' than {max_constraint}, but it is {max_value}'
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            )
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        if type_constraint is not None:
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            min_type_ok = isinstance(min_value, type_constraint)
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            max_type_ok = isinstance(max_value, type_constraint)
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            if not min_type_ok or not max_type_ok:
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                raise ValueError(
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                    f'If "{name}" is a sequence, its values must be of'
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                    f' type "{type_constraint}", not "{type(nums_range)}"'
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                )
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        return nums_range
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    @staticmethod
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    def parse_interpolation(interpolation: str) -> str:
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        if not isinstance(interpolation, str):
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            itype = type(interpolation)
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            raise TypeError(f'Interpolation must be a string, not {itype}')
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        interpolation = interpolation.lower()
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        is_string = isinstance(interpolation, str)
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        supported_values = [key.name.lower() for key in Interpolation]
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        is_supported = interpolation.lower() in supported_values
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        if is_string and is_supported:
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            return interpolation
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        message = (
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            f'Interpolation "{interpolation}" of type {type(interpolation)}'
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            f' must be a string among the supported values: {supported_values}'
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        )
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        raise ValueError(message)
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    @staticmethod
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    def parse_probability(probability: float) -> float:
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        is_number = isinstance(probability, numbers.Number)
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        if not (is_number and 0 <= probability <= 1):
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            message = (
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                'Probability must be a number in [0, 1],'
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                f' not {probability}'
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            )
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            raise ValueError(message)
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        return probability
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    @staticmethod
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    def nib_to_sitk(data: TypeData, affine: TypeData) -> sitk.Image:
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        return nib_to_sitk(data, affine)
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    @staticmethod
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    def sitk_to_nib(image: sitk.Image) -> Tuple[torch.Tensor, np.ndarray]:
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        return sitk_to_nib(image)
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    def get_arguments(self):
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        """
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        Return a dictionary with the arguments that would be necessary to
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        reproduce the transform exactly.
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        """
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        return {name: getattr(self, name) for name in self.args_names}
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    def is_invertible(self):
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        return hasattr(self, 'invert_transform')
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    def inverse(self):
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        if not self.is_invertible():
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            raise RuntimeError(f'{self.name} is not invertible')
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        new = copy.deepcopy(self)
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        new.invert_transform = not self.invert_transform
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        return new
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    @staticmethod
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    @contextmanager
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    def use_seed(seed):
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        """Perform an operation using a specific seed for the PyTorch RNG"""
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        torch_rng_state = torch.random.get_rng_state()
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        torch.manual_seed(seed)
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        yield
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        torch.random.set_rng_state(torch_rng_state)
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    @staticmethod
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    def get_sitk_interpolator(interpolation: str) -> int:
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        return get_sitk_interpolator(interpolation)
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