[ns] nam file

hello;

please i have a probleme with NAM in NS2 simulator, after the simulation,
when i'm trying to open the filenam this mesage is shows "node 0 not
found, node 1 not found) " !!!
this is the biginning of my tcl code
.....
set nf [open outnam.nam w]
$ns namtrace-all-wireless $nf $val(x) $val(y)
......
...
help me please

--
Bien Cordialement
Ben Rhaiem OLFA.
Etudiante Mastère Informatique et Multimédia (I2M).
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