# FilterFunction¶

class FilterFunction(operation, frequencies, exact)

A tensor-valued filter function result.

Variables
• inverse_powers (Tensor) – The values of the filter function at the given frequencies.

• uncertainties (Tensor, optional) – The uncertainties of the filter function values. This field is None when the exact method is used for computing the filter function.

• frequencies (np.ndarray) – The frequencies at which the filter function has been evaluated.

• value_shape (tuple[int]) – The shape of the function value.

• exact (bool) – Indicates whether filter function is exact.

• name (str) – The name assigned to the node.

Notes

The value of a FilterFunction node can be fetched in a graph calculation by adding its name in the output_node_names parameter for the function call. This will add an item to the output dictionary in the calculation result object, whose key is name. The item’s value will be a dictionary with NumPy arrays with the “frequencies” and “inverse_powers” values. If the filter function calculation is not exact, the dictionary also contains an array with the filter function “uncertainties”.