On Fri, 02 Feb 2007 22:29:09 +0000 Ed Catmur <ed@xxxxxxxxxxxx> wrote: >On Fri, 2007-02-02 at 16:30 -0500, zentara wrote: >> Please pardon my basic questions, but I am self taught >> and run into questions I can't solve thru googling. >> >> I see that G_PI is defined in the header to >> 3.14159265358979323846 >> >> So on my 32 bit Athlon machine, I get limited precision >> to 15 decimal places, do I need a 64 bit machine for better >> precision? Or is there a different format to use? > >Google? Did you try Wikipedia? > >double is 64 bits everywhere; 52 bits of mantissa gives 15 decimal >places. (Remember, 1 bit is 0.3 bans). long double may have the >precision you're after, again, read Wikipedia. > >Ed Yeah thanks. I finally was pointed to long double, and did a groups.google search of comp.lang.c for "long double pi" and found alot of discussion on printing more decimal places of accuracy. It's quite an active question. I've tried printing G_PI with the %Lf.20 format and I'm still stuck with 15 decimal places of accuracy. So I will experiment some with defining PI by shifting the decimal place by multiplying and see if the %Lf will do more digits of precision. Something for a Saturday afternoon. :-) zentara -- I'm not really a human, but I play one on earth. http://zentara.net/japh.html _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
