Re: JIT - automated mexing

[Fotios Kasolis]

On Jun 24, 2010, at 9:46 PM, David Bateman wrote:

> Fotios Kasolis wrote:
>> Is there someone that is planing to introduce (or already implementing) JIT 
>> in Octave? If not, i ll place that on my MOST_DESIRED list. Unfortunately i 
>> do not have the knowledge (yet) to do it but i ll start working on that 
>> whenever i find some time (any help: links, books, whatever ;D).
>> 
>> An idea (which i do not know if implementable but sounds so)
>> Instead of a traditional JIT what about automated mexing? Sth like
>> 
>>  
>>> mex_my_loops(myfunc)
>>>    
>> 
>> will replace all (replaceable) loops by mexed ones? Does this sound 
>> reasonable (if not why?)? At least it sounds relatively easier than JIT and 
>> more user oriented (it is always good to have a choice)
>> 
>> /Fotios
>> 
>>  
> I think JIT is a lot harder than you think. There is no strict variable 
> typing in Octave and so you need to discover what types are used before you 
> can call the appropriate compiled functions. Also variable types can be 
> polymorphic. Consider something like
> 
> a = 1
> for i = 0:.1:2
> a += asin(i);
> endfor
> 
> Yes I know its an artifical example, but consider what happens to the type of 
> a when i=1.1.... There is a JIT in FreeMat but FreeMat essentially got rid of 
> there logical and single precision types to simplify the detection of code 
> where the JIT compiler might be applied.
> 
> I'd suggest you look at the JIT code in FreeMat in any case for inspiration, 
> at
> 
> http://freemat.svn.sourceforge.net/viewvc/freemat/branches/ArraySimplification/libs/libMatC/
> 
> Regards
> David
> 

I think of JIT as hard as it is but no more than that! But what about  the 
automated mex code solution?

/Fotios