[Python-Dev] Proposing an alternative to PEP 410 (original) (raw)

Simon Cross hodgestar+pythondev at gmail.com
Sun Feb 26 15:51:08 CET 2012

On Sun, Feb 26, 2012 at 1:31 AM, Guido van Rossum <guido at python.org> wrote:

I still think that when you are actually interested in using times, the current float format is absolutely fine. Anybody who thinks they need to accurately know the absolute time that something happened with nanosecond accuracy is out of their mind; given relativity such times have an incredibly local significance anyway.

There are good scientific use cases for nanosecond time resolution (e.g. radio astronomy) where one is actually measuring time down to that level and taking into account propagation delays. I have first hand experience of at least one radio telescope (MeerKAT) that is using Python to process these sorts of timestamps (Maciej even gave a talk on MeerKAT at PyCon 2011 :).

Often these sorts of applications just use an large integer to hold the time. Higher-level constructs like datetime tend to be too bulky and provide functionality that is not particularly relevant. There is also a lot of pressure to have all the details coded by an in-house expert (because you need complete control and understanding of them, so you might as well do it yourself rather than continually patch, say, Python, to match your instrument's view of how this should all work).

Hardware capable of generating nanosecond accurate timestamps is, however, becoming fairly easy to get hold of (a suitable crystalline clock slaved to a decent GPS unit can get you a lot of the way) and there are probably quite a few applications where it might become relevant.

I'm not sure whether any of this is intended to be for or against any side in the current discussion. :D

Schiavo Simon

More information about the Python-Dev mailing list