Update: Matrix3Dto2D: allow for range of values
So far, the box Matrix3Dto2D asks for 2 parameters: idx of dimension to "remove", and idx within that dimension. See it as a "2D slice" of the input 3D matrix. For example, if input is Frequencies x channels x channels, we can choose to keep "idx N" of dimension 0 (frequencies), hence Frequency N.
However, network graph algos & applications usually need a 2D matrix of average values within (with the previous example, a frequency band).
The user can select dimension 0 and "frequencies from idx 4 to 16", and the box can compute the matrix channels x channels, with each entry being the average across the frequency band of bins [4 to 16]