change of random state when pyc created??

[Steven D'Aprano]

On Sun, 06 May 2007 00:20:04 +0000, Alan Isaac wrote:

>> Should you not expect to get the same result each time? Is that not
>> the point of setting a constant seed each time you run the script?
> 
> Yes.  That is the problem.
> If I delete module2.pyc,
> I do not get the same result.


I think you have missed what John Machin is pointing out. According to
your original description, you get different results even if you DON'T
delete module2.pyc.

According to your original post, you get the _same_ behaviour the first
time you run the script, regardless of the pyc file being deleted or not.
You wrote:

[quote]
module1 sets a seed like this::

if __name__ == "__main__":
    random.seed(314)
    main()

I execute module1.py from the (Windows) shell.
I get a result, let's call it result1.
I execute it again. I get another result, say result2.
Running it again and again, I get result2.
[end quote]

So, with module2.pyc file existing, you get result1 the first time you
execute module1.py, and then you get result2 every time from then onwards.

How is that different from what you wrote next?

[quote]
Now I delete module2.pyc.
I execute module1.py from the shell.
I get result1.
I execute it again; I get result2.
>From then on I get result2,
unless I delete module.pyc again,
in which case I once again get result1.
[end quote]

You get the same behaviour with or without module2.pyc: the first run of
the script gives different results from subsequent runs. You can reset
that first run by deleting module2.pyc.

I'm still perplexed how this is possible, but now I'm more perplexed.

If you want to send me the modules, I will have a look at them as well.
Many eyes make for shallow bugs...



-- 
Steven.