converting numpy datetime64 in a numba jitclass to unix timestamp

Question

For the sake of readability I want to be able to supply a numpy.datetime64 object to a numba jitclass which is converted to a unix epoch timestamp in float format within the class itself.

I currently have to resort to calculating the unix timestamp prior to creating the jitclass object and supply this as a parameter, e.g.:

>>> import numpy as np
>>> (np.datetime64('2024-01-01T00:00:00') - np.datetime64('1970-01-01T00:00:00')) / np.timedelta64(1, 's')
1704067200.0

Suppose that I create the following jitclass that takes a numpy datetime as parameter, how can I create a method within the class that converts the datetime into a unix timestamp? The ultimate goal would be to supply a start and end date when creating the jitclass object, which are then converted to unix timestamps in order to create an array of timestamps using np.arange().

import numpy as np
from numba.experimental import jitclass
from numba import types

spec=[
    ('start', types.NPDatetime('s'))
]

@jitclass(spec)
class Foo():

    def __init__(self, start):
        self.start = start

obj = Foo(np.datetime64('2024-01-01T00:00:00'))

>>> obj.start
numpy.datetime64('2024-01-01T00:00:00')

Andrej Kesely · Accepted Answer · 2024-03-05 21:47:04Z

1

IIUC, you want to create something like to_timestamp() method in the Foo class:

import numba as nb
import numpy as np

spec = [("start", nb.types.NPDatetime("s"))]

_unix_timestamp_begin = np.datetime64("1970-01-01T00:00:00")
_one_second = np.timedelta64(1, "s")


@nb.experimental.jitclass(spec)
class Foo:
    def __init__(self, start):
        self.start = start

    def to_timestamp(self):
        return (self.start - _unix_timestamp_begin) / _one_second


obj = Foo(np.datetime64("2024-01-01T00:00:00"))
print(obj.to_timestamp())

Prints:

1704067200.0

answered Mar 5, 2024 at 21:47

Andrej Kesely

196k15 gold badges60 silver badges105 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

brokkoo Over a year ago

That indeed seems to do the trick. I was under the impression that jitclasses couldn't handle global variables but this seems to work.

Collectives™ on Stack Overflow

converting numpy datetime64 in a numba jitclass to unix timestamp

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related