Re: Is There a Way to Rationalize a Decimal in Pari/GP?

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Thu, Jun 04, 2009 at 09:47:48AM -0400, Rick Regan wrote:
> I'm looking for an automated way to turn a decimal value into a
> fraction in the PARI/GP calculator (gp). For example, I want to turn
> 0.759765625 into 389/512. I know I can do this manually by typing in
> '759765625/10^9', but I'd like an easier way, like
> 'rationalize(0.759765625);' would work in Maxima.

Please use bestappr or contfrac:
? bestappr(0.759765625,10^9)
%1 = 389/512
? contfracpnqn(contfrac(0.759765625))
%2 =
[389 136]

[512 179]

Cheers,
Bill.