object().__dict__

[CHIN Dihedral]

On Wednesday, April 23, 2014 10:21:26 PM UTC+8, Amirouche Boubekki wrote:
> 2014-04-23 15:59 GMT+02:00 Phil Connell <pcon... at gmail.com>:
> 
> 
> 
> On Wed, Apr 23, 2014 at 03:48:32PM +0200, Amirouche Boubekki wrote:
> 
> > 2014-04-23 8:11 GMT+02:00 Cameron Simpson <c... at zip.com.au>:
> 
> 
> > > Look up the "__slots__" dunder var in the Python doco index:
> 
> > >
> 
> > >   https://docs.python.org/3/glossary.html#term-slots
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> > >
> 
> > > You'll see it as a (rarely used, mostly discouraged) way to force a fixed
> 
> > > set of attributes onto a class. As with object, this brings a smaller
> 
> > > memory footprint and faster attribute access, but the price is flexibility.
> 
> > >
> 
> >
> 
> > True, still can be the only way to save few MB or... GB without falling
> 
> > back to C or PyPy.
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> >
> 
> > Have a look at PyPy to how to save memory (and speed things up) without
> 
> > slots:
> 
> > http://morepypy.blogspot.fr/2010/11/efficiently-implementing-python-objects.html
> 
> 
> 
> Is there any analysis of how this balances increased memory usage from the JIT
> 
> vs the CPython VM (with a reasonable amount of code)?
> 
> 
> 
> I'd thought that one of the main disadvantages of PyPy was drastically
> 
> increased memory usage for any decent-sized program. Would be interested to
> 
> know if this was not the case :)
> 
> 
> 
> I have a similar thought, I don't how that memory consumption increase (a constant? a factor? probably both...)
> 
> but if the program use an absurd amount of memory even in CPython then PyPy will be able to catchup based on comment #1 of a PyPy core dev in http://tech.oyster.com/save-ram-with-python-slots/ see also http://pypy.readthedocs.org/en/latest/interpreter-optimizations.html#dictionary-optimizations
> 
> 
> 
> 
> Still it requires more analysis. When does PyPy trigger the optimization?
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>  
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> 
> Cheers,
> 
> Phil
> 
> 
> 
> --
> 
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 The auto-code generation  of valid python codes in PyPy is helpful in CAD/CAM and non-idiot robot brains.