Thanks for your reply, Rabih.

2007/5/31, RABIH.ELCHAAR@sgam.com <RABIH.ELCHAAR@sgam.com>:
>
>  I did a wrapping of the levmar library.
>

Unfortunately, since I am to use this in a commercial product, and I was not
able (yet ?) to convince my boss to release the sources, I can't use with
levmar, wich is GPLed... I may switch to cminpack. But i think this is not
related to my current question.

The approach I chose is to allocate bigarrays from Caml, and pass them to
> the main C function, along with the function f.
>
Does it mean that each time f function is called by the minimization, the C
wrappers has to copy the params C array into your Bigarray pre-allocated
storage place? That's why I choosed to leave the C array untouched and wrap
a Bigarray around it  (should not be a big amount of memory). Am I wrong in
going this way?

In the main function, I register f and all the bigarrays as global roots,
> and then call as many times the c sub function to compute the minimization.


I do not understand this part. f is passed to the main (C) function from
OCaml: why do you need to register it as a global root? Same question for
the Bigarrays? Does it mean that else, nothing in OCaml world would point to
them?
>
> Feel free to ask for more precisions if needed
>
> Hope this helps.
>
Surely. I really need to acquire a better understanding of GC and C
interface in OCaml.
Really, I do not understand what happens to those C allocated Bigarrays...

Salutations

Matthieu