From: Gregory Brown <gregory.t.brown@...>
Date: 2005-12-24T02:07:19+09:00
Subject: Re: BigDecimal#sqrt

On 12/22/05, James Edward Gray II <james@grayproductions.net> wrote:
> I'm trying to understand the argument to BigDecimal#sqrt.  I figured
> it was for precision and it does seem to affect it, but I can't
> understand the exactly relationship.  Can anyone tell me what the
> argument controls and how?

This is the C source, if you haven't looked at it yet.

BigDecimal_sqrt(VALUE self, VALUE nFig)
{
    ENTER(5);
    Real *c, *a;
    S_INT mx, n;

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);

    n = GetPositiveInt(nFig) + VpDblFig() + 1;
    if(mx <= n) mx = n;
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSqrt(c, a);
    return ToValue(c);
}

I don't fully understand what's going on with it, because my C is
pretty weak, but hopefully this will provide some insight from
someone.