Sensor node 位置隨機散佈

for {set i 0} {$i < $val(nn) } { incr i } {
        set n($i) [$ns node]
}

for {set i 1} {$i < $val(nn) } { incr i } {
    $n($i) set X_ [ expr {$val(x) * rand()} ]
    $n($i) set Y_ [ expr {$val(y) * rand()} ]
    $n($i) set Z_ 0
}

#Lable the sink node
$n(0) set X_ [expr {$val(x)/2} ]
$n(0) set Y_ [expr {$val(y)/2} ]
$n(0) set Z_ 0
$ns at 0.0 "$n(0) NodeLabel Sink"

# defines the node size in nam
for {set i 0} {$i < $val(nn)} {incr i} {
   $ns initial_node_pos $n($i) 10
}

NS-2 The first part: pre-definition

1.建立一個模擬器物件 (Must)
   set ns [new Simulator]

2.開啟一個nam trace 檔案 (Option)
   set nf [open out.nam w]
   ns namtrace-all $nf

3.宣告一個finish程序(Must)
   proc finish{}
   {
        global ns nf    #設nf為全域變數
        $ns flush-trace
        #close the trace file
        close $nf
        #execute nam on the trace file
        exec nam out.nam &
        exit 0
   }

data source: http://www.scribd.com/doc/76224756/Network-Simulator-NS-2