The distance matrix for the multidimensional scaling.
If NULL (the default), then the unweighted shortest path
matrix is used.
dim
layout.mds supports dimensions up to the number of
nodes minus one, but only if the graph is connected; for unconnected
graphs, the only possible values is 2. This is because
layout.merge only works in 2D.
options
This is currently ignored, as ARPACK is not used
any more for solving the eigenproblem
Value
A numeric matrix with dim columns.
concept
Graph layout
Details
layout.mds uses metric multidimensional scaling for generating
the coordinates. Multidimensional scaling aims to place points from a
higher dimensional space in a (typically) 2 dimensional plane, so that
the distance between the points are kept as much as this is possible.
By default igraph uses the shortest path matrix as the distances
between the nodes, but the user can override this via the dist
argument.
This function generates the layout separately for each graph component
and then merges them via layout.merge.
References
Cox, T. F. and Cox, M. A. A. (2001) Multidimensional Scaling.
Second edition. Chapman and Hall.