Re: FORTRAN memory issues and use of the sum function 'somme'

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Sat, Jun 25, 2022 at 04:12:56PM +0000, Brereton, Ashley wrote:
> Hi there,
> 
> I was hoping somebody could help with an issue with memory usage.
> 
> My code is written in Fortran. In my code, I have a (simplified) loop (see below). The code fails because the pari stack size isn't big enough.
> 
> It seems like 'u' is stored at a new memory address for each loop iteration, and so the memory fills up - though I may be wrong!

Yes, this is correct, you should read the chapter 'Garbage collection'
of the documentation.

Let say you want to do the sum

   DO I=1_8,100000_8
        u = gadd(u, stor(I,prec))
   ENDDO

you should do
   av = avma
   DO I=1_8,100000_8
        u = gadd(u, stor(I,prec))
        u = gerepilecopy(av, u); 
   ENDDO

or better, only do 'u = gerepilecopy(av, u);' every 1000 iterations or so.

(avma is a global variable from libpari)

Cheers,
Bill.