Richard B. Kreckel
kreckel at ThEP.Physik.Uni-Mainz.DE
Tue Jan 25 18:50:49 CET 2000
On Tue, 25 Jan 2000, Micah McCurdy wrote:
> Forgive this simplistic question, but I'm going around the bend.
> I have an ex, on which I've performed many manipulations, of which I want the
> value. It's a polynomil in x, and evaluating poly.subs(x==valThatIWant) gives
> me another ex, which, when output, is the correct number, to 17 decimal places.
> I need this number as a double value, only to 10 decimal places. What can I do?
You want to convert the ex to a naked numeric first using ex_to_numeric(),
then you can use the method to_double() defined on numeric.
> Setting Digits to various values in various places does not seem to change
> anything. Any help is welcome.
This is because if you, say, increment Digits by one nothing happens
unless a new word for storing the float is touched. This means you have
to increment about 9 Digits on a machine with 32 bit words until you
really get a change. The output function for numerics doesn't do anything
interesting, it falls back to CLN, which is why you see it how CLN stores
<Richard.Kreckel at Uni-Mainz.DE>
To UNSUBSCRIBE, email to ginac-list at ginac.de with a subject of "unsubscribe".
More information about the GiNaC-list