code: public static double ceilingPowerOfBdouble(final double b, final double n) {
      final double x = (n < 1.0) ? 1.0 : n;
      return pow(b, ceil(logB(b, x)));
    }
docs: Computes the ceiling power of B as a double. This is the smallest positive power
  of B that equal to or greater than the given n and equal to a mathematical integer.
  The result of this function is consistent with {@link #ceilingPowerOf2(int)} for values
  less than one. I.e., if <i>n &lt; 1,</i> the result is 1.
  
  @param b The base in the expression &#8968;b<sup>n</sup>&#8969;.
  @param n The input argument.
  @return the ceiling power of B as a double and equal to a mathematical integer.