1 \chapter{Mathematical expressions
}
4 At several points within
\PyX{} mathematical expressions can be
5 provided in form of string parameters. They are evaluated by the
6 module
\verb|mathtree|. This module is not described further in this
7 user manual, because it is considered to be a technical detail. We
8 just give a list of available operators, functions and predefined
13 \verb|+|;
\verb|-|;
\verb|*|;
\verb|/|;
\verb|**|
15 \verb|neg| (negate);
\verb|abs| (absolute value);
\verb|sgn| (signum);
16 \verb|sqrt| (square root);
\verb|exp|;
\verb|log| (natural logarithm);
17 \verb|sin|,
\verb|cos|,
\verb|tan|,
\verb|asin|,
\verb|acos|,
18 \verb|atan| (trigonometric functions in radian units);
\verb|sind|,
19 \verb|cosd|,
\verb|tand|,
\verb|asind|,
\verb|acosd|,
\verb|atand| (as
20 before but in degree units);
\verb|norm| ($
\sqrt{a^
2+b^
2}$ as an
21 example for functions with multiple arguments)
22 \item[predefined variables:
]
23 \verb|pi| ($
\pi$);
\verb|e| ($e$)
