[Tutor] filling 2d array with zeros

[Alex Hall]

On 9/28/10, Dave Angel <davea at ieee.org> wrote:
>
>
> On 2:59 PM, Alex Hall wrote:
>> On 9/28/10, Steven D'Aprano<steve at pearwood.info>  wrote:
>>> <snip>
>>>
>>> PyPy is a version of Python written in Python. It has an incredible
>>> mission: to eventually produce versions of Python which are faster than
>>> pure C, despite being written in Python itself. Although they have a
>>> long, long way to go, they are making good progress, and PyPy can now
>>> run Python code faster than CPython. PyPy is becoming a generalised
>>> Just-In-Time compiler for high-level languages like Python.
>> Okay, I now have to go investigate this and see how it is even
>> possible; somewhere, the Python code has to get down to machine
>> code...
>>
> Just-in-time compiling  (JIT) is taking some high-level construct, such
> as python byte code or a java class file, and compiling it into machine
> code, at the time of first execution.  Java uses it heavily, to achieve
> its performance level.  The standard CPython does not, but simply
> interprets those byte codes.
>
> One advantage of just-in-time is that the translation can be specific to
> a particular processor, or even to a particular operating system and
> operating environment.  Conventional compiling is done by the developer,
> and he has to release multiple versions for multiple platforms.  And
> even then, he seldom takes advantage of the newer instructions of a
> given processor, which are changing quite frequently.  I'm sure there
> are at least a dozen different instruction supersets of the original
> Pentium processor, though most of the recent ones are relatively
> specialized (eg. for hashing, searching, encryption), and likely to
> affect libraries more than your main program.
Thanks for the info. That explains why Pypy said it only works on
Intel-based systems for the moment, and why special things must be
done for 64-bit processors.
>
> DaveA
>
>


-- 
Have a great day,
Alex (msg sent from GMail website)
mehgcap at gmail.com; http://www.facebook.com/mehgcap