Was curious as to the speed of floating point operations on the 16MHz Arduino Diecimila. Could only find a few threads about that (e.g., http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1206534749), with no answer, so I ran some tests.
As the person who started the other thread thank you for that.
I must say I'm surprised it can do doubles so fast. Do you have data for division? With division algorithms, you'll need to test a wide range of denominators to get a good feel.
BTW, double is supposed to be 8-bytes: http://www.arduino.cc/en/Reference/Double
I don't know why sizeof() would return 4.