could anyone tell me about this error, please?
num_nodes is set 22
INITIALIZE THE LIST xListHead
(_o18 cmd line 1)
invoked from within
"_o18 cmd port-dmux _o31"
invoked from within
"catch "$self cmd $args" ret"
invoked from within
"if [catch "$self cmd $args" ret] {
set cls [$self info class]
global errorInfo
set savedInfo $errorInfo
error "error when calling class $cls: $args" $..."
(procedure "_o18" line 2)
(SplitObject unknown line 2)
invoked from within
"$agent port-dmux $dmux_"
(procedure "_o15" line 11)
(Node/MobileNode add-target-rtagent line 11)
invoked from within
"$self add-target-rtagent $agent $port"
(procedure "_o15" line 23)
(Node/MobileNode add-target line 23)
invoked from within
"$self add-target $agent $port"
(procedure "_o15" line 15)
(Node attach line 15)
invoked from within
"$node attach $ragent [Node set rtagent_port_]"
(procedure "_o3" line 79)
(Simulator create-wireless-node line 79)
invoked from within
"_o3 create-wireless-node"
("eval" body line 1)
invoked from within
"eval $self create-wireless-node $args"
(procedure "_o3" line 23)
(Simulator node line 23)
invoked from within
"$ns_ node"
("for" body line 2)
invoked from within
"for {set i 0} {$i < $val(nn)} {incr i} {
set node_($i) [$ns_ node]
$node_($i) random-motion 0
$ns_ initial_node_pos $node_($i) 20
}"
(file "demo1_rad2.tcl" line 131)
