Does including signatures to numba improve speed?

Question

Does including the input/output signatures in the @jit decorator improve speed in any significant way?

Answer 1

While it won't improve the execution speed of the compiled code, it will change when the compilation is done.

When specifying the signatures, it compiles the functions at the time they are defined in your code (eager compilation), whereas if you do not specify them, they are compiled when they are called (lazy compilation).

So while it won't have an effect on the speed of your function, it may affect the speed of your program, depending on when it is compiled. If compilation must be avoided during runtime, you can run the function once, and then proceed with the execution of your full code so that it will already be compiled when needed.

The documentation regarding this can be found here.