topic cumsum of CGA array in ArcGIS CityEngine Questions

cumsum of CGA array

MagnusLundevall — Wed, 22 Feb 2023 07:39:46 GMT

How can I get "cumsum" of an array in CGA? Iterate and build a new array recursively in some way?

Re: cumsum of CGA array

JonasObertuefer — Wed, 22 Feb 2023 10:06:55 GMT

Yes exactly, here is an example:

cumsum(array) = cumsum(array, 1) cumsum(array, i) = case size(array) <= i: array else: cumsum(setElems(array, i, array[i]+array[i-1]), i+1) Init --> print(cumsum([2,5,1,3.5,8]))

May I ask about the usecase? If it is something common we might add it as builtin function in the future, so you don't have to rely on recursion for this.

Cheers,
Jonas

Re: cumsum of CGA array

MagnusLundevall — Wed, 22 Feb 2023 11:26:58 GMT

Thanks! I have used it in trying to solve Split face into rectangular pieces - Esri Community
I extract scope.sx for each face edge in an array and want to process it to compute split x's.
I also had the need for min(array) and max(array) that return the smallest and largest element, respectively. I did write them in the same recursive manner. It would be great to have these in CGA.

Re: cumsum of CGA array

JonasObertuefer — Wed, 22 Feb 2023 12:31:04 GMT

I see. Thanks for the informations.

For min/max of an array there is currently no dedicated function, but you can use sortIndices(), there is an example for this case in the cga reference: https://doc.arcgis.com/en/cityengine/latest/cga/cga-sort-indices-function.htm