9:01 AM
@user21 Sound like the life I'm sometimes dreaming about :-) But sometimes I imagine it on a sailboat. My wife says the boat must have a proper shower at an absolute minimum to live on it full-time, which is probably beyond our means :(
When an array is passed to a LibraryLink function with that accepts any array type (Real, Integer, Complex), Mathematica must determine the type of that array and pack it if necessary.
Is there a way to do this with excellent performance manually?
I am hoping that there would be some internal functions to help with this.
I am trying to implement a system where the type would be automatically detected and a C++ template function would be called with the appropriate template argument. E.g. fun<mint> or fun<double> based on whether the passed value on the Mathematica side was an integer or real.
For scalars, this detection is easy in pure Mathematica with pattern matching.
For arrays, this detection is easy on the C side: just pass the array as is, without detecting its type. Then on the C side use MTensor_getType.
But I want to the flexibility to have functions analogous to this: template<typename T> tensor<T> multiplyTensor(T x, tensor<T> arr) (C++ish peusocode). This would multiply an array with a scalar of matching type.
This function has both a scalar and a tensor argument. The scalar type can only be detected on the Mathematica side and as for the tensor element type: I only know how to detect it on the C side with good performance (which is critical).
I need to detect them on the same side, either C or Mathematica, then dispatch to the appropriate specialized function.
I see two solutions: either detect the array type in Mathematica, or instead of sending scalars "as-is", wrap them into a list and send them like that: that allows postponing the type detection to C.
Of course there's still the problem of deciding what to do if the function is called with non-matching types :(
I really need to speak to someone about this before I sit down to implement it (and discover at the end, after a lot of work, that I was taking the wrong approach). It's a pity that there's no one here(where I live) who uses Mathematica and also LibraryLink
I will try to break these down into smaller and clearly written questions and post them on main. Even if I don't get an answer, it should help me organize my thoughts. The next best thing after being able to talk to someone "irl".
