I can get the sigma object to load, but I get a slient fail upon rendering

Performing a web search gave me:

https://stackoverflow.com/questions/32863277/sigma-js-graph-doesnt-render-anything

Tada!

Actually, I found my canvas had no height, only a width. Specifying a height and other properties, like in the stackoverflow link:

#graph-container {
  max-width: 400px;
  height: 400px;
  margin: auto;
}

solves the problem of displaying a graph...