Method isMathematicalInteger

output/java_guava/1.4.19/DoubleMath.java:279–284

Returns true if x represents a mathematical integer. This is equivalent to, but not necessarily implemented as, the expression !Double.isNaN(x) && !Double.isInfinite(x) && x == Math.rint(x).

(double x)

   */

  @GwtIncompatible // java.lang.Math.getExponent, com.google.common.math.DoubleUtils
  public static boolean isMathematicalInteger(double x) {
    return isFinite(x)
      && (x == 0.0
          || SIGNIFICAND_BITS - Long.numberOfTrailingZeros(getSignificand(x)) <= getExponent(x));
  }

  /**
   * Returns {@code n!}, that is, the product of the first {@code n} positive integers, {@code 1} if