Logarithms in Java BigInteger

[Arne Vajhøj]

ah I see I was confused just thought you wanted to change the base so it could be calculated by an easier to create base 10 log.

But wouldn't it then be ?
return ln(v.divide(TWO)).add(LNTWO);
You wanted to calculate it recursively right?

Yes.

You are absolutely correct.

Arne

 

[Richard Zapor]

Given zBD=BigDecimal(10).pow(1000), 10^1000 the log10 of zBD (integer) for any length zBD can be created with limited mantissa precision via zstr=char(zBD.toString()); Length_zBD=length(zstr);
Log10_z=Length_zBD+log10(str2num(['.' zstr]))
For numbers with decimals the length is digits to the decimal point and then final calculation needs the decimal removed from zstr.
The precision is based on precision for double.