polyexp¶

sofia_redux.toolkit.fitting.polynomial.polyexp(order, ndim=None, indexing='j')[source]¶

Returns exponents for given polynomial orders in arbitrary dimensions.

Similar to toolkit.resampling.resample_utils.polynomial_exponents, but specialized for the polynomial fitting functions in toolkit.fitting.

Parameters:

orderint or array_like of int: Polynomial order for which to generate exponents. If an array will create full polynomial exponents over all len(order) dimensions.
ndimint, optional: If set, return Taylor expansion for ndim dimensions for the given order if order is not an array.
indexingstr, optional: {‘i’, ‘j’} If ‘i’, then if order = [nx, ny], exponents are ordered as [[y0, x0], [y1, x0], [yn, x0],…, [y1, x0]., … if ‘j’, then if order = [nx, ny], exponents are ordered as [[x0, y0], [x1, y0], [xn, y0], …, [x0, y1], …

Returns:

exponentsnumpy.ndarray

Polynomial exponents for the given order. Will be of shape:

order ndim shape ———- —- ————————————————— int None (order+1,) array (n,) None (array[0]+1, array[1]+1, …, array[n-1]+1) int n (ncoeffs, ndim) where ncoeffs is a Taylor expansion

Examples

>>> polyexp(3)
array([0, 1, 2, 3])

>>> polyexp([1, 2], indexing='i')
array([[0, 0],
       [1, 0],
       [2, 0],
       [0, 1],
       [1, 1],
       [2, 1]])

>>> polyexp([1, 2], indexing='j')
array([[0, 0],
       [1, 0],
       [0, 1],
       [1, 1],
       [0, 2],
       [1, 2]])

>>> polyexp(2, ndim=2)
array([[0, 0],
       [1, 0],
       [2, 0],
       [0, 1],
       [1, 1],
       [0, 2]])

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polyexp¶