qiskit-community / qiskit-dynamics

Tools for building and solving models of quantum systems in Qiskit
https://qiskit-community.github.io/qiskit-dynamics/
Apache License 2.0
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Fix complex cast warning #329

Closed DanPuzzuoli closed 8 months ago

DanPuzzuoli commented 9 months ago

Summary

This PR modifies the code to eliminate complex -> real casting warnings that have popped up at various places.

Details and comments

To do this I've changed code in a couple places in which a tensordot occurs between a real and complex array. The change is essentially converting np.tensordot(x, y) to np.tensordot(x, y.real) + 1j * np.tensordot(x, y.imag) (where x is typically real and y is the complex array).

This eliminated all of the warnings - I'm not 100% sure about efficiency but I'm hoping it shouldn't change anything, as I assume the cost of arithmetic of np.tensordot(x, y) for y complex is twice that of when y is imaginary.