Large archive problem

[Will Woods]

Hi,

I am working with large matrices (~100x100) and had trouble with restoring
archives of them. I wrote the attached test program which just adds the
same expression to an archive n times (with a unique name each time).
For any n, the expression can always be retrieved from the original
archive. But reloading it from file into a new archive object only
succeeds for n<108 (in this case - other size expressions have different
limits).

Great package though. Our problem solution went from several hours under
Macsyma to just 36 seconds with GiNaC!


Will


System:

GiNaC 0.8.0
CLN 1.1.0
Linux Mandrake 7.2
AMD 700Mhz 128Mb




-------------- next part --------------
#include "iostream.h"
#include <cstdio>
#include <fstream>
using namespace std;

#include <ginac/ginac.h>
using namespace GiNaC;


int main()
{
    //    const int n = 108;               //Archive is corrupted after saving and loading
        const int n = 107;                 //Works fine

        archive ar;
        symbol x("x"),y("y"),z("z");

        ex foo = sin(x+2*y)+3*z+41;

        char nme[10];

        for (int i = 0; i < n; i++) {
                sprintf(nme,"foo%d",i);
                ar.archive_ex(foo,nme);
        }

        //Save this archive to a file
        ofstream fout("test.gar");

        fout << ar;
        fout.close();


        //Reload it from file into a new archive
        archive ar2;

        ifstream fin("test.gar");

        fin >> ar2;
        fin.close();


        try{

                ex ex1 = ar.unarchive_ex(lst(x,y),"foo0");   //Works fine for both cases
                cout << "Original archive gives " << ex1 << endl;

                // Fails for too large an archive with message
                // "expression with name 'foo0' not found in archive"
                ex ex2 = ar2.unarchive_ex(lst(x,y),"foo0");
                cout << "Reloaded archive gives " << ex2 << endl;

        } catch (exception &e) { cout << e.what() << endl; }



}