Method log

src/main/java/com/rtg/util/MathUtils.java:286–296

Compute an approximation to the natural logarithm. Assumes parameter is positive and finite. @param x parameter @return ln(x)

(final double x)

   * @return <code>ln(x)</code>
   */
  public static double log(final double x) {
    assert x >= 0 && Double.isFinite(x);
    if (x == 0.0) {
      return Double.NEGATIVE_INFINITY;
    }
    final long t = Double.doubleToRawLongBits(x);
    final long lg = (t >>> EXPONENT_OFFSET) - EXPONENT_BIAS;
    final int mantissa = (int) (t >> (EXPONENT_OFFSET - BITS));
    final double mlg = LOG_TABLE[mantissa & MASK];
    return mlg + lg * LOG_2;
  }

  /**
   * Get a phred-scaled quality value corresponding to the supplied error rate.