[com4]: Initialize raster arrays consistently

[PaulaSp3]

• we have now the function, that "overrides" all not affected cells with a specific value (default: -9999)
• Should we initialize now all arrays consistently with np.zeros() or np.ones() * -9999 ?: in flowCore.py lines 473-501 and in lines 263-278

[ahuber-bfw]

Hm, I think it's ok if we have some of the arrays initiated with '0' and some with '-9999'.
Especially for the results where we sum up the values of individual paths having the result arrays initialized with '0' makes the code a bit shorter/easier, since we don't have to check for potentially adding to negative values ...

...but of course initializing everything with '0' might work and should also be faster (I will check the code and see if this works in combination with the 'affected cells' function)

--> btw, initializing with np.empty does not save RAM and is only marginally faster than initializing with np.zeros

what's your opinion?

[PaulaSp3]

Yes, you're right. Initiating with '-9999' does not make sense.

When initiating '0' , in travelLengthMin, travelAngleMin: we could get values > 0 in cells that are startcells (although the actual minimum is 0 since there is a startcell.) I'm not so sure, if it is better to get 0 in every start cell in the minimum-layers or getting the minimum value of other paths in this cell.