That is another odd feature of using the interpretter. Since I do a new on TMatrix for H you would expect that the right way to access the elements is
(*H)(0,0) = 1.0
However, this doesn’t work on the interpreter.
I have been being rather lazy about writing things and just using the interpreter rather than complining and then loading them as a shared library. I suppose the latter would be better for catching errors and higher likelyhood of success.