### 对称矩阵(Matrix)格式转网络(Network)数据集格式函数
### 本函数适用于无向网络图

##  网络数据格式适用于R/Gephi/Pajek等;对称矩阵格式适用于Ucinet等
#######################                 ####################### 
# 网络数据标准数据格式#        #        #  矩阵标准数据格式   #
#######################       #         #######################
# source target value #      ########   #   a       b      c  # 
#   a      b     2    #       #         #a  0       2      2  #
#   a      c     2    #        #        #b  2       0      4  #
#   b      c     4    #                 #c  2       4      0  #  
#######################                 #######################              

TraMtoN <- function(network,N)          #N为网络节点无重复个数
{
  network<-as.data.frame(network)
  p.names <- names(network)
  if(!all(p.names == rownames(network))) 
    stop("origin is not consistent with destination.")
  network <- data.frame(
                     origin=rep(p.names,each=N),
                     destination=rep(p.names,N),
                     Weight=as.vector(t(network)))
  network<- network[!(network$origin == network$destination),]
  return(network)
}

#EXAMPLE
A <- matrix(c(0,2,2,2,0,4,2,4,0),3,3)
dimnames(A) <- list(c("A","B","C"),c("A","B","C"))
TraMtoN(A,3)

##Author
# JianCheng Li
# School of Economics ＆ Management 
# Zhejiang University of Technology 
# No.288.Liuhe Road, Hangzhou, Zhejiang, P.R.China, 310000