How to use GraphViz graphs in DiagrammeR for R

Question

I am trying to use a GraphViz graph in DiagrammeR. How can I do this?

myGraph = grViz("
digraph boxes_and_circles {

  # a 'graph' statement
  graph [overlap = true, fontsize = 10]

  # several 'node' statements
  node [shape = box,
        fontname = Helvetica]
  A; B; C; D; E; F

  node [shape = circle,
        fixedsize = true,
        width = 0.9] // sets as circles
  1; 2; 3; 4; 5; 6; 7; 8

  # several 'edge' statements
  A->1 B->2 B->3 B->4 C->A
  1->D E->A 2->4 1->5 1->F
  E->6 4->6 5->7 6->7 3->8
}
")

and then I want to use it in DiagrammeR, but it will not allow it.

render_graph(myGraph)

Gives:

Error: class(graph) == "dgr_graph" are not all TRUE

Is there a way I need to convert or input the GraphViz graph into the DiagrammeR environment?

grViz returns an object of class htmlwidget and not a dgr_graph. You can visalize directly myGraph. use create_graph function from DiagrammeR to be able to use render_graph. — tokiloutok, Aug 24 '16 at 22:28
Unfortunately, `gd = create_graph(myGraph)` gives the following error `Error: "nodes" %in% colnames(nodes_df) is not TRUE` -- I don't understand how to specify DiagrammeR graphs using GraphViz. If this isn't possible, then why does the DiagrammeR literature spend so much time talking about GraphViz? I mean, it says "Graphviz support is an integral part of the DiagrammeR package." -- If that's true, how do they connect? — ollama, Aug 24 '16 at 23:49

score 4 · Accepted Answer · answered Aug 25 '16 at 06:07

grViz takes a string describing the graph (vis.js style) : it is the interpreted by vis.js. Its return value is then an htmlwidget object.

render_graph takes a dgr_graph object, created using the create_graph function.

you can see in the DiagrammeR doc

library(DiagrammeR)

# Create a simple NDF
nodes <-
  create_nodes(
    nodes = 1:4,
    type = "number")

# Create a simple EDF
edges <-
  create_edges(
    from = c(1, 1, 3, 1),
    to = c(2, 3, 4, 4),
    rel = "related")

# Create the graph object,
# incorporating the NDF and
# the EDF, and, providing
# some global attributes
graph <-
  create_graph(
    nodes_df = nodes,
    edges_df = edges,
    graph_attrs = "layout = neato",
    node_attrs = "fontname = Helvetica",
    edge_attrs = "color = gray20")

# View the graph
render_graph(graph)

DiagrammeR can produce Graphviz code : From the doc mentioned below : "If you'd like to return the Graphviz DOT code (to, perhaps, share it or use it directly with the Graphviz command-line utility), just use output = "DOT" in the render_graph()"

So

you can use create_graph to produce graphviz dot code
you can use graphviz dot code directly with grViz in DiagrammeR

good answer, and just to make sure that it is clear, there is no function in `DiagrammeR` that converts `DOT` to a `dgr_graph`. `DiagrammeR` is designed to go the other way and focused on helping to build the network and render output. — timelyportfolio, Aug 25 '16 at 10:38
Got it, so DOT / GraphViz is used primarily for visualization from DiagrammeR but not for graph creation — ollama, Aug 25 '16 at 15:25
Somehow the documentation makes it hard to knowhow to render a graph. — NelsonGon, Dec 03 '18 at 17:16

score 0 · Answer 2 · answered Nov 11 '20 at 13:24

Here the problem is with ~~render_graph(myGraph)~~, using just myGraph works like charm.

library(DiagrammeR)

myGraph = grViz("
digraph boxes_and_circles {

  # a 'graph' statement
  graph [overlap = true, fontsize = 10]

  # several 'node' statements
  node [shape = box,
        fontname = Helvetica]
  A; B; C; D; E; F

  node [shape = circle,
        fixedsize = true,
        width = 0.9] // sets as circles
  1; 2; 3; 4; 5; 6; 7; 8

  # several 'edge' statements
  A->1 B->2 B->3 B->4 C->A
  1->D E->A 2->4 1->5 1->F
  E->6 4->6 5->7 6->7 3->8
}
") 

myGraph

~~render_graph(myGraph)~~ Does not work in R.

Just myGraph works fine.

How to use GraphViz graphs in DiagrammeR for R

2 Answers2