[Numpy-discussion] matlab vs. python question

David Cournapeau david@ar.media.kyoto-u.ac...
Thu Apr 26 07:42:07 CDT 2007


Sturla Molden wrote:
> On 4/26/2007 2:19 PM, Steve Lianoglou wrote:
>
>>> Beside proper programing paradigm Python easily scales to large- 
>>> scale number crunching: You can run large-matrices calculations  
>>> with about 1/2 to 1/4 of memory consumption comparing to Matlab.
>> Is that really true? (The large-matrix number crunching, not the  
>> proper programming paradigm ;-)
>>
>> By no scientific means of evaluation, I was under the impression that  
>> the opposite was true to a smaller degree.
>
> Matlab have pass-by-value semantics, so you have to copy your data in 
> and copy your data out for every function call. 
You are true for the semantics, but wrong for the consequences on 
copying, as matlab is using COW, and this works well in matlab. I have 
never noticed a big difference between matlab and python + numpy for 
memory consumption; I fail to see any reason why it would be 
significantly different (except the fact that numpy does not have to use 
double, whereas matlab had to for a long time, and double is still the 
default on matlab).

David


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