Draw a graph

TDA's graph-drawing command, pltree, only draws trees. For anything else – a cycle, more than one component, or a directed graph – this lays the nodes out on a circle and draws it with tda_pl_graph instead, which takes explicit coordinates and so can draw any graph.

Usage

# S3 method for class 'tda_graph'
plot(
  x,
  width = 110,
  height = 80,
  file = "graph.ps",
  newpage = TRUE,
  layout = c("auto", "circle", "tree"),
  ...
)

Arguments

x

a tda_graph.

width, height

size of the plotting area in millimetres.

file

name for the PostScript file.

newpage

start a new page before drawing.

layout

"auto" (the default) uses pltree when the graph is actually a tree (connected, one fewer edge than nodes) and a circular layout otherwise; "circle" always uses the circular layout, "tree" always tries pltree and lets TDA refuse a non-tree graph with its own error.

...

further options for pltree (layout = "tree") or tda_pl_graph (layout = "circle").

Value

The parsed drawing operations, invisibly.

See also

Other graph analysis: tda_dmet(), tda_g(), tda_g_analyses, tda_graph(), tda_locate_line(), tda_ptree(), tda_ucl()

Examples

e <- data.frame(from = c(1, 1, 2), to = c(2, 3, 4), value = 1)
g <- tda_graph(e, directed = FALSE)  # 4 nodes, 3 edges: already a tree
pdf(NULL); plot(g); dev.off()
#> agg_record_1f9b21c6ab0b 
#>                       2 

# a graph with a cycle is not a tree, and this one is directed besides --
# both are fine with the default circular layout
e2 <- data.frame(from = c(1, 1, 2, 2, 3, 4), to = c(2, 3, 3, 4, 4, 5))
g2 <- tda_graph(e2, directed = TRUE)
pdf(NULL); plot(g2); dev.off()
#> agg_record_1f9b21c6ab0b 
#>                       2