R/incidence_matrix.R

In HyperG: Hypergraphs in R

## HyperG R Package
## 
## Copyright (c) 2021 David J. Marchette <dmarchette@gmail.com>
## 
## Permission is hereby granted, free of charge, to any person obtaining a copy
## of this software and associated documentation files (the "Software"), to deal
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## copies of the Software, and to permit persons to whom the Software is
## furnished to do so, subject to the following conditions:
## 
## The above copyright notice and this permission notice shall be included in all
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## 
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## IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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## 

incidence_matrix <-
function(g)
{
	if(is.hypergraph(g)) {
	   return(hypergraph_as_incidence_matrix(g))
	}
	s <- gsize(g)
	n <- gorder(g)
   M <- Matrix::Matrix(0,nrow=s,ncol=n,dimnames=list(NULL,V(g)$name))
	edges <- igraph::as_edgelist(g)
	for(i in 1:nrow(edges)){
		M[i,edges[i,]] <- 1
	}
	M
}

hypergraph_as_incidence_matrix <- function(h)
{
   h$M
}