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Interpolation Utility Functions

This module contains basic paraxial interpolation functions.

scale

Paraxially interpolates a square array based on the sampling ratio, and npixels_out.

Parameters:

Name Type Description Default
array Array

The input field to interpolate, either in amplitude and phase, or real and imaginary.

 required
npixels int

The number of pixel in the output array.

 required
ratio float

The scale of the input relative to the output

 required
method str = "linear"

The interpolation method.

 'linear'

Returns:

Name Type Description
array Array

The interpolated array.
Source code in src/dLux/utils/interpolation.py 
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def scale(
    array: Array, npixels: int, ratio: float, method: str = "linear"
) -> Array:
    """
    Paraxially interpolates a square array based on the sampling ratio, and npixels_out.

    Parameters
    ----------
    array : Array
        The input field to interpolate, either in amplitude and phase, or real
        and imaginary.
    npixels : int
        The number of pixel in the output array.
    ratio : float
        The scale of the input relative to the output
    method : str = "linear"
        The interpolation method.

    Returns
    -------
    array : Array
        The interpolated array.
    """
    # Get coords arrays
    npixels_in = array.shape[-1]
    coords_in = dlu.pixel_coords(npixels_in, 1)
    coords_out = dlu.compress_coords(
        dlu.pixel_coords(npixels, 1),
        np.array([ratio, ratio]) * npixels / npixels_in,
    )

    # Interpolate
    return interp(array, coords_in, coords_out, method)
rotate

Rotates a square array by the angle, using interpolation.

Parameters:

Name Type Description Default
array Array

The array to rotate.

 required
angle (Array, radians)

The angle to rotate the array by.

 required
method str = "linear"

The interpolation method.

 'linear'

Returns:

Name Type Description
array Array

The rotated array.
Source code in src/dLux/utils/interpolation.py 
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def rotate(array: Array, angle: Array, method: str = "linear") -> Array:
    """
    Rotates a square array by the angle, using interpolation.

    Parameters
    ----------
    array : Array
        The array to rotate.
    angle : Array, radians
        The angle to rotate the array by.
    method : str = "linear"
        The interpolation method.

    Returns
    -------
    array : Array
        The rotated array.
    """
    # Get coordinates
    npixels = array.shape[0]
    coords_in = dlu.nd_coords((npixels, npixels))
    coords_out = dlu.rotate_coords(coords_in, angle)

    # Interpolate
    return interp(array, coords_in, coords_out, method)