forsean.R

plot_net = function(nodes_per_layer, layer_shape, connection_type, stride_length){
  total_nodes = sum(nodes_per_layer)
  adjacency = matrix(0,nrow=total_nodes,ncol=total_nodes)
  
  for(i in seq_along(connection_type)){
    
    source_nodes = 1:nodes_per_layer[i] + (i-1 > 0)*sum(nodes_per_layer[1:(i-1)])
    sink_nodes = 1:nodes_per_layer[(i+1)] + (i > 0)*sum(nodes_per_layer[1:i])
      
    nsource = length(source_nodes)
    nsink = length(sink_nodes)
    
    if(connection_type[i] == "straight"){
      if(nsource!=nsink){
        stop(paste("Can't use straight at layer",i,"because # of nodes doesn't match"))
      }else{
        adjacency = index_assign(source_nodes,sink_nodes,adjacency)
      }
    }else if(connection_type[i] == "full"){
       adjacency = index_assign(rep(source_nodes,each=nsink),
                                rep(sink_nodes,nsource),adjacency)
    }else if(connection_type[i] == "convolution"){
      if(stride_length[i] > nodes_per_layer[(i+1)]){
        stop(paste("Can't use stride length",stride_length[i],"at layer",i,"because not enough nodes."))
      }else{
          adjacency = index_assign((0:(stride_length[i]-1)) + rep(source_nodes,each=stride_length[i]),
            rep(sink_nodes,each=stride_length[i]),adjacency)
      }
    }
  }
}

index_assign = function(x,y,mat){
  for(i in seq_along(x)){
    mat[x[i],y[i]] = 1
  }
  mat
}