5

Is it possible to use more than one \pgfmathparse and pgfmathresult in a single macro?

In this MWE, I try to use two of each. It did not quite work. The fraction on top should say 10/3, not 0.3/3.

What am I missing?

\documentclass{article}

\usepackage{tikz}

\newcommand{\NLdot}[5] %{xscale}{yscale}{xmax}{denom}{xval of dot}
{\tikz[xscale=#1,yscale=#2]
{
 \draw (0,0)--(#3,0);
 \pgfmathparse{#3*#4}
 \foreach \x in {0,...,\pgfmathresult}
  \draw (\x/#4,-0.2)--(\x/#4,0.2);
 \foreach \x in {0,...,#3}
  \node[below] at (\x,-0.3) {\x};
 \fill[gray,opacity=0.5] (#5,0) circle [x radius = 0.2/#1, y radius = 0.2/#2];

% This didn't work... would like a fration label right above the dot. Why did I get 0.3 instead of 10 for the numerator?
 \pgfmathparse {#4*#5} 
  \node[above] at (#5,0.3) {$\frac{\pgfmathresult}{#4}$}
}
}


\begin{document}

\NLdot{2.5}{1.25}{5}{3}{10/3}

\end{document}

1 Answer 1

5

The \pgfmathresult is often set and used by other stuff, in this case probably the \node (the y-coordinate is 0.3, so seems a likely candidate). Moving the \pgfmathparse to immediately before the \pgfmathresult solves this.

Another option is to save the result to a macro with \pgfmathsetmacro{\<macro name>}{<calculation>}.

One final point: If you know that the numerator in your cases will always become an integer (as here, with 3*10/3), then you can use for example the int function to avoid getting 10.0 as output. All of this is demonstrated in the example below.

enter image description here

\documentclass{article}

\usepackage{tikz}

\newcommand{\NLdotA}[5] %{xscale}{yscale}{xmax}{denom}{xval of dot}
{\tikz[xscale=#1,yscale=#2]
{
 \draw (0,0)--(#3,0);
 \pgfmathsetmacro{\EndOfForLoop}{#3*#4}
 \foreach \x in {0,...,\EndOfForLoop}
  \draw (\x/#4,-0.2)--(\x/#4,0.2);
 \foreach \x in {0,...,#3}
  \node[below] at (\x,-0.3) {\x};
 \fill[gray,opacity=0.5] (#5,0) circle [x radius = 0.2/#1, y radius = 0.2/#2];

\pgfmathsetmacro{\TheNumerator}{int(#4*#5)}
  \node[above] at (#5,0.3) {$\frac{\TheNumerator}{#4}$}
}
}

\newcommand{\NLdotB}[5] %{xscale}{yscale}{xmax}{denom}{xval of dot}
{\tikz[xscale=#1,yscale=#2]
{
 \draw (0,0)--(#3,0);
 \pgfmathparse{#3*#4}
 \foreach \x in {0,...,\pgfmathresult}
  \draw (\x/#4,-0.2)--(\x/#4,0.2);
 \foreach \x in {0,...,#3}
  \node[below] at (\x,-0.3) {\x};
 \fill[gray,opacity=0.5] (#5,0) circle [x radius = 0.2/#1, y radius = 0.2/#2];


  \node[above] at (#5,0.3) {$\frac{\pgfmathparse{#4*#5}\pgfmathresult}{#4}$}
}

\begin{document}

\noindent\NLdotA{2}{1.25}{5}{3}{10/3}

\noindent\NLdotB{2}{1.25}{5}{3}{10/3}

\end{document}

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