## Extensions to MathML 2 functions for DAVE-ML applications

Listed on this page are additional functions used frequently in dynamic simulation
models that are not defined as part of MathML 2.

### Linear Interpolation tables

This capability is provided in DAVE-ML through use of the breakpointDef, griddedTableDef,
ungriddedTableDef, and function elements of DAVE-ML.

See the DAVE-ML reference manual for more information
about function representations.

### Atan2

This function provides a two-argument arc tangent function, similar to those
available in ANSI C and FORTRAN math libraries as well as Microsoft Excel and
Mathworks Matlab and Simulink products.

The following definition from the GNU 4.0.1 gcc `man`

page is reproduced for reference:

*The ***atan2** function computes the principal value of
the arc tangent of y/x, using the signs of both arguments to determine
the quadrant of the return value.

The first argument (*y*) represents the opposite side of the
angle and the second (*x*) the adjacent, non-hypotenuse side.
The resultant represents the angle, in radians, in the range of
–π to +π.

Implementation of this function is up to the processing application.