Hi Lindsay, > Having just tried it... I am surprised that the 'sqrt* I implemented is > quite a bit faster! than the built-in 'sqrt. I'll try the long division > later.
Wow, that's indeed a bit surprising. However, it depends on the scale, and I think a can explain (see below). > : (scl 100000) (bench (nil (sqrt 2.0))) # Built-in > 30.917 sec > -> NIL > : (scl 100000) (bench (nil (sqrt* 2.0))) # > 2.906 sec Which scale did you use here? If I try 2 : (scl 2) -> 2 : (bench (do 1000000 (sqrt 2.0 1.0))) # Built-in 0.106 sec -> 141 : (bench (do 1000000 (sqrt* 2.0))) 5.052 sec -> 141 and then bigger ones, : (scl 20) -> 20 : (bench (do 100000 (sqrt 2.0 1.0))) # Built-in 1.435 sec -> 141421356237309504880 : (bench (do 100000 (sqrt* 2.0))) 6.103 sec -> 141421356237309504880 the built-in is a quite faster. But for bigger scales : (scl 64) -> 64 : (bench (do 10000 (sqrt 2.0 1.0))) # Built-in 1.269 sec -> 14142135623730950488016887242096980785696718753769480731766797380 : (bench (do 10000 (sqrt* 2.0))) 0.762 sec -> 14142135623730950488016887242096980785696718753769480731766797379 the built-in is slower. I think this is because the built-in 'sqrt' first multiplies with the scale (just as we do before a division), and thus calculates with bignums of double length. I think this is necessary for a precise result. ♪♫ Alex -- UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe
