Math.sol

pragma solidity 0.4.25;

import "./SafeDecimalMath.sol";

library Math {

    using SafeMath for uint;
    using SafeDecimalMath for uint;

    /**
    * @dev Uses "exponentiation by squaring" algorithm where cost is 0(logN)
    * vs 0(N) for naive repeated multiplication. 
    * Calculates x^n with x as fixed-point and n as regular unsigned int.
    * Calculates to 18 digits of precision with SafeDecimalMath.unit()
    */
    function powDecimal(uint x, uint n)
        internal
        pure
        returns (uint)
    {
        // https://mpark.github.io/programming/2014/08/18/exponentiation-by-squaring/

        uint result = SafeDecimalMath.unit();
        while (n > 0) {
            if (n % 2 != 0) {
                result = result.multiplyDecimal(x);
            }
            x = x.multiplyDecimal(x);
            n /= 2;
        }
        return result;
    }
}