interp can not handle datetime64, while fix seems easy

[mbakker7]

The interp function can not handle datetime64 dtypes (docs are not explicit about this; they state that x and xp should be values). Error message is that array cannot be cast to dtype('float64') according to the rule 'safe'. But conversion seems easy.

Reproducing code example:

import numpy as np
d1 = np.datetime64('2019-01-01')
d2 = np.datetime64('2019-01-03')
xp = np.array([d1, d2])
yp = np.array([1, 3])
x = np.datetime64('2019-01-02')
np.interp(x, xp, yp)  # produces error

while the following works fine

np.interp(x.astype('float64'), xp.astype('float64'), yp)

So why is that not done in the interp function?

[madphysicist]

If I'm not mistaken, np.ndarray.astype always makes a copy, while np.asfarray (with the appropriate flags) only makes one as necessary, so might be a better choice.

[seberg]

Well .astype(..., copy=False) also exists.