This is done using C++ generic functions to get/set the real/imag parts of complex numbers. This gives us an easy way to support Numpy v < 2.0, and allows the type underlying the bit width types, like pytensor_complex128, to be correctly inferred from the numpy complex types they inherit from. Updated pytensor_complex struct to use get/set real/imag aliases defined above. Also updated operators such as `Abs` to use get_real, get_imag. Macros have been added to ensure compatibility with numpy < 2.0 Note: redefining the complex arithmetic here means that we aren't treating NaNs and infinities as carefully as the C99 standard suggets (see Appendix G of the standard). The code has been like this since it was added to Theano, so we're keeping the existing behavior.