Important fix for the creation of the multi dimensional pA numpy array.
It should be created as numpy.zeros([ei][si][mi][oi]) instead of numpy.ones([ei][si][mi][oi]).
This allows for rapid testing of all dimensions with np.allclose(pA, numpy.ones(dw.shape)).
pA can have missing filled out values, when the number of dispersion points are different
per spectrometer frequency.
Task #7807 (https://gna.org/task/index.php?7807): Speed-up of dispersion models for Clustered analysis.
