hotstepper.Sequency.ifwt

Sequency.ifwt(fwt_data, scale=None, return_length=None)

Perform an inverse Fast Discrete Walsh Transform on the input data. The input data is expected to be an array representing the transform amplitudes from a Walsh transform of a dataset. This method will use the amplitude data to reconstruct the original dataset using the provided ammplitudes matrix. The scale of the Walsh basis functions can be specified explcitly using the scale parameter, else if this parameter is not explicitly set, the scale value will be derived from the length of the fwt_data (amplitude) array.

Parameters

• fwt_data (array_like) – The Walsh transform amplitudes to use to reconstruct the dataset.

• scale (int, Optional) –

  The scale (length) of the Walsh functions to use when performing the inverse Walsh transform.

  Note

  This value must be a multiple of 2 or an exception will be raised.

return_lengthint, Optional

The length of the reconstructed dataset, as the length of the original data may not be a multiple of 2, the scale of the Walsh functions used in thr transform (fwt) method may be shorter or longer, therefore when returning a reconstruction, you can specify a length to truncate the reconstuction at.

Returns

reconstructed dataset

Return type

array

References