protected static Ptg calcRoman( Ptg[] operands )
	{
		int[] numbers = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 };
		String[] letters = { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" };
		String roman = "";
		if( operands.length == 1 )
		{
			double dd = operands[0].getDoubleVal();
			if( new Double( dd ).isNaN() ) // Not a Num -- possibly PtgErr
			{
				return PtgCalculator.getError();
			}

			int i = (int) dd;
			if( (i < 0) || (i > 3999) )
			{
				return PtgCalculator.getError(); // can't write nums that high!
			}
			for( int z = 0; z < numbers.length; z++ )
			{
				while( i >= numbers[z] )
				{
					roman += letters[z];
					i -= numbers[z];
				}
			}
		}
		PtgStr pstr = new PtgStr( roman );
		return pstr;
	}