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Padding

Centered padding and cropping operations for tensors.

torchlinops.functional.center_pad 

center_pad(
    x: Tensor,
    im_size: tuple[int, ...],
    pad_im_size: tuple[int, ...],
)

Center pads the input tensor to the specified size.

PARAMETER DESCRIPTION
x

The input tensor to be padded.

TYPE: Tensor

im_size

The original size of the input tensor.

TYPE: tuple of int

pad_im_size

The desired size after padding.

TYPE: tuple of int

RETURNS DESCRIPTION
Tensor

The padded tensor.
Notes

This function uses the Pad operator to perform the padding operation. It calculates the necessary padding dimensions and applies the padding to ensure that the output tensor matches the pad_im_size while preserving the center of the original tensor.

Source code in src/torchlinops/functional/_pad.py 
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def center_pad(x: Tensor, im_size: tuple[int, ...], pad_im_size: tuple[int, ...]):
    """
    Center pads the input tensor to the specified size.

    Parameters
    ----------
    x : Tensor
        The input tensor to be padded.
    im_size : tuple of int
        The original size of the input tensor.
    pad_im_size : tuple of int
        The desired size after padding.

    Returns
    -------
    Tensor
        The padded tensor.

    Notes
    -----
    This function uses the `Pad` operator to perform the padding operation.
    It calculates the necessary padding dimensions and applies the padding
    to ensure that the output tensor matches the `pad_im_size` while preserving
    the center of the original tensor.
    """
    ndim = len(im_size)
    pad = pad_to_size(im_size, pad_im_size)
    crop_slice = crop_slice_from_pad(pad)
    pad_linop = SimpleNamespace(
        im_size=im_size,
        pad_im_size=pad_im_size,
        D=ndim,
        pad=pad,
        crop_slice=crop_slice,
    )
    return Pad.fn(pad_linop, x)

torchlinops.functional.center_crop 

center_crop(
    x: Tensor,
    im_size: tuple[int, ...],
    crop_im_size: tuple[int, ...],
)

Center crops the input tensor to the specified size.

PARAMETER DESCRIPTION
x

The input tensor to be cropped.

TYPE: Tensor

im_size

The original size of the input tensor.

TYPE: tuple of int

crop_im_size

The desired size after cropping.

TYPE: tuple of int

RETURNS DESCRIPTION
Tensor

The cropped tensor.
Notes

This function uses the Pad operator to perform the cropping operation. It calculates the necessary cropping dimensions and applies the cropping from the center of the original tensor to achieve the specified crop_im_size.

Source code in src/torchlinops/functional/_pad.py 
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def center_crop(x: Tensor, im_size: tuple[int, ...], crop_im_size: tuple[int, ...]):
    """
    Center crops the input tensor to the specified size.

    Parameters
    ----------
    x : Tensor
        The input tensor to be cropped.
    im_size : tuple of int
        The original size of the input tensor.
    crop_im_size : tuple of int
        The desired size after cropping.

    Returns
    -------
    Tensor
        The cropped tensor.

    Notes
    -----
    This function uses the `Pad` operator to perform the cropping operation.
    It calculates the necessary cropping dimensions and applies the cropping
    from the center of the original tensor to achieve the specified `crop_im_size`.
    """
    ndim = len(im_size)
    pad = pad_to_size(crop_im_size, im_size)
    crop_slice = crop_slice_from_pad(pad)
    crop_linop = SimpleNamespace(
        im_size=crop_im_size,
        pad_im_size=im_size,
        D=ndim,
        pad=pad,
        crop_slice=crop_slice,
    )
    return Pad.adj_fn(crop_linop, x)