From http://www-106.ibm.com/developerworks/library/wi-elite17.html?ca=dnt-435

// very fast square root approximation public final static int sqrt( long val ) { long temp, g = 0, b = 0x8000, bshft = 15; do { if( val >= ( temp = ( ( ( g << 1 ) + b ) << bshft-- ) ) ) { g += b; val -= temp; } } while( ( b >>= 1 ) > 0 ); return (int)g; }

Hang on... that casts the answer into an int. That's a little TOO approximate for my liking. -- Tango

It's also about 10 times slower than Math.sqrt() on my machine... Maybe this whole idea was bad. :-p --David Alves

I think a lot of these functions are implemented in hardware, so making interpreted software variants may not help. -- Kawigi