The math.functions.integer-logs vocabulary provides exact integer logarithms for all rational numbers:
Examples
integer-log2 ( x -- n )
integer-log10 ( x -- n )
Examples
USING: prettyprint math.functions.integer-logs sequences ;
{
5 99 100 101 100000000000000000000
100+1/2 1/100
} [ integer-log10 ] map .
{ 0 1 2 2 20 2 -2 }
{ 0 1 2 2 20 2 -2 }