McCoy Group References

FiniteDifferenceFunction

The FiniteDifferenceFunction encapsulates a bunch of functionality extracted from Fornberger’s Calculation of Wieghts in Finite Difference Formulas (https://epubs.siam.org/doi/pdf/10.1137/S0036144596322507)

Only applies to direct product grids, but each subgrid can be regular or irregular

Properties and Methods

regular_difference: method
from_grid: method

__init__(self, *diffs, axes=0, contract=False): 

Constructs an object to take finite differences derivatives of grids of data

diffs: FiniteDifference1D

A set of differences to take along successive axes in the data
axes: int | Iterable[int]

The axes to take the specified differences along
contract: bool

Whether to reduce the shape of the returned tensor if applicable after application

apply(self, vals, axes=None, mesh_spacing=None, contract=None): 

Iteratively applies the stored finite difference objects to the vals

vals: np.ndarray

The tensor of values to take the difference on
axes: int | Iterable[int]

The axis or axes to take the differences along (defaults to self.axes)
:returns: np.ndarray

The tensor of derivatives

__call__(self, vals, axes=None, mesh_spacing=None): 

@property
order(self): 

:returns: tuple[int]

the order of the derivative requested

@property
weights(self): 

:returns: tuple[np.array[float]]

the weights for the specified stencil

@property
widths(self): 

:returns: tuple[(int, int)]

the number of points in each dimension, left and right, for the specified stencil

Examples