This function tries to choose an appropriate graph layout algorithm for the graph, automatically, based on a simple algorithm. See details below.
layout_nicely(graph, dim = 2, ...)nicely(...)
A numeric matrix with two or three columns.
The input graph
Dimensions, should be 2 or 3.
For layout_nicely
the extra arguments are passed to
the real layout function. For nicely
all argument are passed to
layout_nicely
.
Gabor Csardi csardi.gabor@gmail.com
layout_nicely
tries to choose an appropriate layout function for the
supplied graph, and uses that to generate the layout. The current
implementation works like this:
If the graph has a graph attribute called ‘layout’, then this is used. If this attribute is an R function, then it is called, with the graph and any other extra arguments.
Otherwise, if the graph has vertex attributes called ‘x’ and ‘y’, then these are used as coordinates. If the graph has an additional ‘z’ vertex attribute, that is also used.
Otherwise,
if the graph is connected and has less than 1000 vertices, the
Fruchterman-Reingold layout is used, by calling layout_with_fr
.
Otherwise the DrL layout is used, layout_with_drl
is called.
In layout algorithm implementations, an argument named ‘weights’ is
typically used to specify the weights of the edges if the layout algorithm
supports them. In this case, omitting ‘weights’ or setting it to
NULL
will make igraph use the 'weight' edge attribute from the graph
if it is present. However, most layout algorithms do not support non-positive
weights, so layout_nicely
would fail if you simply called it on
your graph without specifying explicit weights and the weights happened to
include non-positive numbers. We strive to ensure that layout_nicely
works out-of-the-box for most graphs, so the rule is that if you omit
‘weights’ or set it to NULL
and layout_nicely
would
end up calling layout_with_fr
or layout_with_drl
, we do not
forward the weights to these functions and issue a warning about this. You
can use weights = NA
to silence the warning.
plot.igraph
Other graph layouts:
add_layout_()
,
component_wise()
,
layout_as_bipartite()
,
layout_as_star()
,
layout_as_tree()
,
layout_in_circle()
,
layout_on_grid()
,
layout_on_sphere()
,
layout_randomly()
,
layout_with_dh()
,
layout_with_fr()
,
layout_with_gem()
,
layout_with_graphopt()
,
layout_with_kk()
,
layout_with_lgl()
,
layout_with_mds()
,
layout_with_sugiyama()
,
layout_()
,
merge_coords()
,
norm_coords()
,
normalize()