As libre currency have exponential growing number property, we must care about a programming limitation: integer variables types maximum value.

#### Metab brouzouf experience

With Meta brouzouf, we simulate more than 330 years duration which on average 15 members creating money. Meta brouzouf monetary mass is 64.10¹⁸ MB which is up than a `long int`

which is 2⁶³ - 1 = 9.10¹⁸ units. That’s not the case of UD which is today 0.5 10¹⁸ MB.

uCoin softwares are using int type bigger than `long int`

.

#### Problem

In a production libre currency, when big numbers could arrived? We know growing rate is about 10% per year. But we don’t know about the number of members.

#### Simulation

So, I try a simulation, which calculate M and UD.

Hypothesis:

- monetary mass growth c = +10%/year as recommended by RTM.
- we consider number of members N constant.
- Initial UD is 100 units.
- UD calculation is always calculated with UD = c × M/N

Libre currency - big number simulation.ods (9,6 Ko)

You could change N (number of members).

#### Conclusion

My conclusion is that 30 years of libre currency duration (Bitcoin is ~7 years duration) with:

- N = 1.000 members, M go to 1.7 10⁶ MB and UD go to 1.7 10³ MB.
- N = 1.000.000 members, M go to 1.7 10⁹ and UD go to 1.7 0³ MB.

It’s not a problem for less than 30 years and less than 1 M members. It could be an issue for longer duration and more members.