':param normalise:       should vectors be normalised to length 1
:type normalise:        boolean
:param svd_dimensions:  number of dimensions to use in reducing vector
dimensionsionality with SVD
:type svd_dimensions:   int'

def __init__(self, normalise=False, svd_dimensions=None):

    self._Tt = None
    self._should_normalise = normalise
    self._svd_dimensions = svd_dimensions
