R/methods-multiGraph.R

In graph: graph: A package to handle graph data structures

##some methods for the multigraph class

setMethod("show", signature("multiGraph"),
          function(object) {
              numNodes<- numNodes(object)
               cat("A", class(object), "with \n")
              cat("Number of nodes =", numNodes, "\n")
              cat("Number of edge lists =", length(object@edgeL), "\n")
          })

setMethod("isDirected", "multiGraph",
	  function(object)
          sapply(object@edgeL, isDirected))


setMethod("nodes", signature(object="multiGraph"),
          function(object)  object@nodes)

setMethod("numNodes", signature(object="multiGraph"),
          function(object) length(nodes(object)))


setMethod("edges", signature(object="multiGraph"),
          function(object, which) {
              nV = nodes(object)
              if (missing(which))
                  which <- nV
              lapply(object@edgeL, function(x) edges(x, which, nV))
          })

setMethod("numEdges", signature(object="MGEdgeSet"), 
          function(object) {
              attr(object@bit_vector, "nbitset")
          }) 

setMethod("numEdges", signature(object="multiGraph"),
          function(object) {
              sapply(object@edge_sets, numEdges)
    
          })

  #
  #numEHelper = function(gEdges, directed) {
  #    if (length(gEdges) == 0)
  #        return(length(gEdges))
  #    numEdges <- length(unlist(gEdges, use.names=FALSE))
  #    if (directed) {
  #        numSelfLoops <- sum(mapply(function(e, n) sum(n == e),
  #                                   gEdges, names(gEdges)))
  #        numEdges <- numSelfLoops + (numEdges - numSelfLoops) / 2
  #    }
  #    numEdges
  #}
  #    
  #setMethod("numEdges", signature(object="multiGraph"),
  #          function(object) {
  #              gEdges <- edges(object)
  #              dir <- isDirected(object)
  #              ans <- rep(NA, length(dir))
  #              for(i in 1:length(dir))
  #                  ans[i] = numEHelper(gEdges[[i]], dir[i])
  #              ans
  #          })
  #


##we need a validity checking method: ensure that nodes are the same
##in all edgeSets - which is hard as the edgeSets don't always seem to
##know

#####edgeSet methods here

##this is a bit dangerous as these are not really the nodes of the
##graph - we don't enforce having all nodes in the adj matrix

setMethod("isDirected", "edgeSet",
	  function(object) edgemode(object) == "directed")

setMethod("edgemode", "edgeSet", function(object) edgemode(object))

setMethod("show", signature("edgeSet"),
          function(object) {
              numEdge<-numEdges(object)
              cat("A", class(object), "with", edgemode(object), "edges\n")
              cat("Number of Edges =", numEdge, "\n")
          })


###edgeSetAM methods

setMethod("nodes", signature(object="edgeSetAM"),
          function(object)  rownames(object@adjMat))

setMethod("edges", signature(object="edgeSetAM"),
          function(object, which, nodes) {
              stopifnot( is.character(which) )
              stopifnot( is.character(nodes) )
              idx <- base::which(colnames(object@adjMat) %in% which)
              getEdgeList(object@adjMat[idx, ], nodes[idx])
          })

setMethod("numEdges", signature(object="edgeSetAM"),
          function(object) {
              nE <- sum(object@adjMat != 0)
              if (!isDirected(object)) {
                  selfLoops <- sum(diag(object@adjMat) != 0)
                  nE <- selfLoops + (nE - selfLoops)/2
              }
              nE
          })

          
##edgeSetNEL methods here
##and here we are a bit scuppered by the way we represent the edge
##lists - we need to have the node set around

setMethod("edges", signature(object="edgeSetNEL"),
          function(object, which, nodes) {
              stopifnot( is.character(which) )
              stopifnot( is.character(nodes) )
              lapply(object@edgeL[which], function(x) nodes[x$edges])})