\section{Installation and compilation}

\subsection{Files}

The package consists of two files:
\begin{itemize}
  \item \tkzname{tkz-fn.sty}: the \LaTeX{} interface (macros and options);
  \item \tkzname{tkz\_fn.lua}: the Lua code (computations and generated \TIKZ\ code).
\end{itemize}

Both files must be placed in a folder known to \TeX{}, for example \tkzname{texmf/tex/latex/tkz-fn}, or in the folder of the document.

\subsection{Loading}

\begin{tkzltxexample}[]
\usepackage{tkz-fn}         % format according to the language of babel
\usepackage[us]{tkz-fn}     % American format of the results
\usepackage[fr]{tkz-fn}     % French format of the results
\end{tkzltxexample}

\TIKZ\ and its library \tkzname{plotmarks} are loaded automatically. Some \TIKZ\ options used in the examples need other libraries: |\usetikzlibrary{arrows,patterns}|.

\subsection{Compilation}

The document must be compiled with \tkzname{LuaLaTeX}. The \tkzname{shell-escape} option is not needed and no auxiliary file is created.

\subsection{Writing functions}

Expressions are Lua expressions. The variable is |x| for a function, |t| for a parametric or a polar curve.

\begin{center}
\begin{tabular}{lll}
\toprule
Lua & old syntax (gnuplot) & description \\
\midrule
|x^3|, |x^0.5| & |x**3|, |x**0.5| & power \\
|1/3| & |1./3| & quotient (always decimal) \\
|ln(x)| or |log(x)| & |log(x)| & natural logarithm \\
|log10(x)| & |log10(x)| & common logarithm \\
|exp(x)|, |e| & |exp(x)|, |exp(1)| & exponential, number $\text{e}$ \\
|sqrt(x)|, |abs(x)| & |sqrt(x)|, |abs(x)| & square root, absolute value \\
|sin|, |cos|, |tan| & same & radians \\
|asin|, |acos|, |atan| & same & inverse functions \\
|sinh|, |cosh|, |tanh| & same & hyperbolic functions \\
|pi| & |pi| & $\pi$ \\
|floor|, |ceil|, |sign|, |mod(a,b)| & |floor|, |ceil|, |sgn|, |%| & \\
|cbrt(x)|, |root(x,n)| & & cube root, $n$-th root \\
\bottomrule
\end{tabular}
\end{center}

\tkzHand A function defined with \tkzcname{tkzFnDef} can be used in another expression: |2*f(x)+1|. A global Lua variable can be used as a parameter: |\directlua{a = 0.5}| then |a*x^2|.

\tkzHand The functions |diff(f,x)|, |integral(f,a,b)| and |riemann(f,a,b,n,"left")| give the derivative at a point, the integral (Simpson's rule) and a Riemann sum. They are used with \tkzcname{tkzFnPrint}.

\tkzBomb An argument between parentheses must not contain an unprotected closing parenthesis: write |(f,{1/exp(1)})|, not |(f,1/exp(1))|.

\endinput