> <somewhat-back-on-topic> > So knowing this... is the fractional math how the BC Math extension for > PHP works? I'm really curious now. It certainly makes things more > clear for me if this is the case. > </somewhat-back-on-topic> Somewhat. I'd more describe it as: "You pick how many decimal points you want BC_MATH to use, and BC_MATH will juggle the string representations of your numbers to keep that many decimals valid" So if you choose 10 decimal points, BC_MATH will represent 0.999... as: "0.9999999999" and 1 as "1.0000000000" and then it will add/subtract/multiply with that many decimal points. For scientific usage, to keep your rounding "correct" you always use an "extra" decimal place than you are claiming as your accuracy, so that any round-off errors happen in a decimal place you're not pretending is "correct". Note that all the operations happen as string-parsing, so you're basically limited to the size of your RAM for your strings to fit. And, as you might imagine, it is NOT going to be anything like as fast as using built-in operators, since it has to munge all the strings to get answers. If you're an astrophysicist or a nuclear researcher, you NEED that precision, though. YMMV (but not by more than N decimal places) :-) -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
