Good morning everyone,

I am trying to integrate a Python function with NIntegrate[ ].
In general, to evaluate a Python function from Mathematica, I evaluate the independent variable of the function into a number, convert the number to a string and then call the Python function, as happens in the code below, see (*example of call*):

The problem arises into NIntegrate[ ] which apparently is not passing to externalF[ ] a number but still a symbolic variable x which is then given to Python as a string of value 'x', and thus rising the error.

I tried the "SymbolicProcessing" -> False option but it did not help. Any help would be greatly appreciated!

EDIT: I appended ?NumericQ as:

externalF[u_?NumericQ] := 
 ExternalEvaluate[session, 
  "special.ellip_harm(1,2,1,2," <> ToString[u] <> 
   ")"]

and now the following integration is working (I compared it with Python integration):

NIntegrate[externalF[x], {x, 0.5, 1}]

Are there downsides in doing this?