/// <summary>Calculate Log2 of a BigInteger object value.</summary>
/// <remarks>Calculate Log2 of a BigInteger object value.</remarks>
/// <param name="val">BigInteger object value which will calculate with log2</param>
/// <returns>Result of calculating of val as double value</returns>
public static double logBigInteger(BigInteger val)
{
double LOG2 = java.lang.Math.log(2.0);
int blex = val.bitLength() - 1022;
if (blex > 0)
{
val = val.shiftRight(blex);
}
double res = java.lang.Math.log(val.doubleValue());
return blex > 0 ? res + blex * LOG2 : res;
}