Calculate the timescales and spatial functions of the separation of variables approach, using the algorithm by (Major, 1993).
The (reciprocals) of the timescales (i.e. the roots of the transcendental equation) are stored in the somanode. The spatial factors are stored in each (computational) node.
maxspace_freq (float (default is 500)) – roughly corresponds to the maximal spatial frequency of the smallest time-scale mode