

PyPy 1.8 - business as usual - bivab
http://morepypy.blogspot.com/2012/02/pypy-18-business-as-usual.html

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mynegation
PyPy to me looks like a great effort and a technological tour de force. But I
wish they would talk _more_ about why and when PyPy will be _slower_ than
CPython on their site . Here is why.

I tried to run some of my scripts on PyPy and performance was invariably worse
(about 50% worse). And my first reaction was: PyPy is not delivering on its
promises. Only later, on some forum I read that PyPy does not perform well on
large dictionaries (and this is essentially what I do in my scripts). Have I
known it in advance, my first impression of PyPy would be much better.

~~~
fijal
It's the creation of large dicts to be precise. The thing is we try to attack
those problems as they arise and as people report bugs. Generally pypy slower
than cpython is a bug and we consider it as such. That also means that those
are moving targets usually - as we discover this, we fix it and sometime maybe
something else pops up. It would be a bit of a mess to keep the list of such
things on the website.

~~~
scott_s
Do you have a web-facing bug tracking system?

~~~
obtu
<https://bugs.pypy.org/>

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RyanMcGreal
I'd love to see a list of diffs: things that work in CPython and don't work in
PyPy. That would be much more helpful for me to decide if it's time to switch.

~~~
ch0wn
Here you go:

<http://doc.pypy.org/en/latest/cpython_differences.html>

<http://pypy.org/compat.html>

<https://bitbucket.org/pypy/compatibility/wiki/Home>

------
unwind
Can somebody please fix the title? It hurts.

~~~
Symmetry
At first I thought it some some subtle dig at PyPy for not being feature
complete or something.

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hencq
Would the work on numpypy also make e.g. scipy available? Or would a separate
effort be needed to move that to PyPy? Their website (scipy.org) mentions it
builds on numpy, but it's unclear to me if it also depends on other libraries.

 _Edit:_ I see the scipy website also mentions this:

    
    
      Various SciPy modules use Fortran 77 libraries and some use C++, so you'll also need Fortran 77 and C++ compilers installed. The SciPy module Weave uses a C++ compiler at run time.

So I guess it wouldn't work out of the box. Do the PyPy devs have any plan for
this as well?

~~~
fijal
This is an example approach how this might work -
[http://morepypy.blogspot.com/2011/12/plotting-using-
matplotl...](http://morepypy.blogspot.com/2011/12/plotting-using-matplotlib-
from-pypy.html)

~~~
obtu
This one is a great big hack…

