Re: [pure-lang-users] case

[Albert G. <Dr....@t-...>]

Eddie Rucker wrote:
> What about complex? So I still have to have a setter function for double
> and complex, so I might as well include integers.

Yes, sure. I didn't suggest that you should throw the int setter routine 
out of the window. You have an int setter routine that takes an int 
matrix and int values. Then you have a double setter routine which takes 
a double matrix and either an int (which gets promoted to double) or a 
double value. Etc., you get the idea. No need for that type argument to 
the setter routines.

Coming to think of it, it's even better if you write a wrapper function 
for each type of matrix in C, which takes a list (as a pure_expr*) as 
argument and returns a matrix. That would execute *much* faster since 
you only have a single function call per matrix. (You don't initialize a 
big matrix with n^2 function calls in C either, or do you? If GSL 
doesn't provide a direct way to initialize a big matrix then that'd be a 
major performance hog.)

Well, obviously I don't have an idea how you initialize a matrix in GSL. 
Can you point me to some C code which shows how to do this? Then I'll be 
able to sketch out how you can make it work using the Pure API. It 
should really be easy.

> Now, if I could only find a portable way of determining the size of word
> boundaries for different machines and OSs ...

I still don't understand why you need that. Just to access the 
dimensions of the matrix? As I suggested earlier, all accesses to the 
matrix struct can and should be wrapped up in C routines, then you don't 
need that kind of hack.

> I really hate to add a C
> wrapper on top of a C interface and then a Pure wrapper on top of the C
> wrapper but it's definitely looking to be the best route.

Yes, it is. The Q modules work that way, too. When you have a complex C 
library, almost invariably you need some additional support routines for 
accessing the data, and that stuff is best written in C. Then you have a 
little Pure module which hides away all the complexity, loads the 
necessary C libraries and provides any high-level definitions 
(overloading operators etc.) that you want. All the Pure programmer ever 
sees is that Pure script.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag