Violin technique once. "Double stopping" is also used to mean playing on three or all four strings at once, although such practices are more properly called "triple" or "quadruple stopping". Collectively, double, triple and quadruple stopping is called "multiple stopping". However, triple or quadruple stopping is more commonly just called a chord. Sounding an open string alongside a fingered note is another way to get a harmony. While sometimes also called a double stop, it is more properly called a drone, as the drone note (the open string) may be sustained for a passage of different notes played on the adjacent string.
Quadruple-precision floating-point format the double-double technique above, although that technique does not implement IEEE quadruple precision), since direct hardware support for quadruple precision is, as of 2016, less common (see "Hardware support" below). One can use general arbitrary-precision arithmetic libraries to obtain quadruple (or higher) precision, but specialized quadruple-precision implementations may achieve higher performance. A separate question is the extent to which quadruple-precision types are directly incorporated into computer programming languages. Quadruple precision is specified in Fortran by the codice_2 (module codice_3 from Fortran 2008 must be used, the constant codice_4 is equal to 16 on most processors), or as codice_5, or in