igraph arrow.mode seems to have no effect

Question

I have a network with some directed and some undirected edges. I'm trying to use igraph to plot it using the arrow.mode parameter, but the graph is always showing arrows with default parameters. Here's an example

Here are some data:

spearRhoP_lagged4 <- structure(list(Var1 = c("ARISA_538.9", "ARISA_538.9", "ARISA_666.4", 
"ARISA_686.9", "ARISA_538.9", "ARISA_594.1"), Var2 = c("ARISA_666.4", 
"ARISA_686.9", "ARISA_686.9", "ARISA_666.4", "ARISA_561.8", "ARISA_561.8"
), rho = c(0.280885191364122, 0.415365287156247, 0.614493076574831, 
0.312630564055403, 0.295296877306726, 0.381890811408216), p = c(0.00206314544835896, 
2.9098006351119e-06, 1.35005674822095e-13, 0.000567475872663549, 
0.00116911931220592, 1.98010880043619e-05), delay = c(0, 0, 0, 
1, 0, 0), fdr = c(0.0135393920048557, 7.97032347878478e-05, 2.83511917126399e-11, 
0.00503534929264839, 0.00898225813036257, 0.000366902513022), 
    arrow = c("-", "-", "-", ">", "-", "-")), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -6L), groups = structure(list(
    Var1 = c("ARISA_538.9", "ARISA_538.9", "ARISA_538.9", "ARISA_594.1", 
    "ARISA_666.4", "ARISA_686.9"), Var2 = c("ARISA_561.8", "ARISA_666.4", 
    "ARISA_686.9", "ARISA_561.8", "ARISA_686.9", "ARISA_666.4"
    ), .rows = list(5L, 1L, 2L, 6L, 3L, 4L)), row.names = c(NA, 
-6L), class = c("tbl_df", "tbl", "data.frame"), .drop = TRUE))

Then I build the graph

LaggedSpearGraph <- graph_from_data_frame(spearRhoP_lagged4)

Lastly I plot the graph, telling it that I want the arrow direction to be specified by the parameter arrow

plot(LaggedSpearGraph,
      vertex.size=2,
      arrow.mode = E(LaggedSpearGraph)$arrow)

I get an output that looks like this.

But what I want is a network where there is only one edge with an arrow on it.

Any suggestions?

desval desval · Accepted Answer · 2020-05-06T15:18:11

You need to add edge as a prefix:

LaggedSpearGraph <- graph_from_data_frame(spearRhoP_lagged4, directed=T)

plot(LaggedSpearGraph,
     vertex.size=10,
     edge.arrow.mode = E(LaggedSpearGraph)$arrow)

See here: https://github.com/igraph/igraph/issues/954

igraph arrow.mode seems to have no effect

1 Answers