How To Efficiently Create A Tuple Of Length N With Code That Will Compile With Numba?

I timed two ways to create a tuple of length N. This is very fast: def createTuple(): for _ in range(100000): tuplex = (0,) * 1000 CPU times: user 439 ms, sys: 1.01 m

Solution 1:

From the numba (0.50) documentation:

Note

The tuple() constructor itself is NOT supported.

So, in numba code, tuples need to be either supplied as function arguments or initialized as literals, like (0, 1, 2, 3). This is unfortunate, because it means that operations involving array shapes require tuples in numba, even though they work fine with int arrays in regular numpy:

shape = np.arange(1, 4)
np.zeros(shape) # OK for normal python code, not in an @njit function.

You'll have to refactor your code to have tuple creation outside the @njit function:

@njitdeffoo(tup):
   ...

foo(tuple(np.zeros(100)))

Unfortunately, tuple(np.zeros(100)) is relatively slow.