/**
  * Is the given year a year year in the Gregorian Calendar?
  * @param yyyy the year
  * @return true if the year is a leap year
  */
public static final boolean isLeapViaPopeGregory ( int yyyy )
   {
   if ( yyyy < 0 ) return( yyyy + 1 ) % 4 == 0;
   if ( yyyy < 1582 ) return yyyy % 4 == 0;
   if ( yyyy % 4 != 0 ) return false;
   if ( yyyy % 100 != 0 ) return true;
   if ( yyyy % 400 != 0 ) return false;
   return true;
   }