How to scale a tikz graph

Question

I would like to enlarge a diagram made with the \graph command, because the arrows at the current scale look too short to me. The options I have tried, however, seem to have no effect. I have tried scale, sibling distance, node distance, node sep, level distance, and possibly others. I am compiling with LuaTeX. I have a feeling I am missing something simple. I would just like to magnify it, similar to what the scale option would do to other tikz pictures.

\documentclass[12pt]{amsart}

\usepackage{tikz}

\usetikzlibrary{arrows,trees,graphs}

\usetikzlibrary{graphdrawing}
\usegdlibrary{trees,force}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\begin{document}

\[ 
\begin{tikzpicture}
    \graph[clockwise=7,math nodes, edges = {double equal sign distance, -implies}] { "p_1", "p_2", "p_3", "p_4", "p_5", "p_6", "p_7"; "p_1" -> "p_2" -> "p_3" -> "p_4" -> "p_5" -> "p_6" -> "p_7" -> "p_1" }; 
\end{tikzpicture}
\]

\end{document}

This is the current output:

Thank you!

Answer 1

Pass the option radius=<value> to the \graph command.

\documentclass[12pt]{amsart}
\usepackage{tikz}
\usetikzlibrary{arrows,trees,graphs}
\usetikzlibrary{graphdrawing}
\usegdlibrary{trees,force}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\begin{document}

\begin{tikzpicture}
    \graph[clockwise=7,radius=3cm,math nodes, edges = {double equal sign distance, -implies}] { "p_1", "p_2", "p_3", "p_4", "p_5", "p_6", "p_7"; "p_1" -> "p_2" -> "p_3" -> "p_4" -> "p_5" -> "p_6" -> "p_7" -> "p_1" }; 
\end{tikzpicture}
\end{document}