C++ definition: click here
A LOGO-style movement model, with the script coming from XML. It can be useful for describing random as well as deterministic scenarios.
First, a few examples.
Node will move along a square's borders:
<movement> <set speed="10" angle="180"/> <repeat n="4"> <forward d="50"/> <turn angle="90"/> </repeat> </movement>
MassMobility (in which the node is assumed to have a mass, and cannot turn abruptly):
<movement> <repeat> <set speed="uniform(10,20)"/> <turn angle="uniform(-30,30)"/> <forward t="uniform(0.1,1)"/> </repeat> </movement>
<movement> <repeat> <set speed="uniform(20,60)"/> <moveto x="uniform(0,$MAXX)" y="uniform(0,$MAXY)"/> </repeat> </movement>
Commands (XML element names) are: repeat, set, forward, turn, wait, moveto, and moveby.
Attribute values can be literal numbers (e.g. x="100"), or any distribution accepted in omnetpp.ini (e.g. speed="uniform(10,20)"). A new value will be chosen each time the statement is executed. The $MAXX and $MAXY strings will be substituted with the playground width and height minus 1, respectively.
t is time interval, calculated from the end of the previous movement. x, y are absolute coordinates with <set> and <moveto>, and relative with <moveby>. angle is clockwise in degrees, with 0 pointing west. d is distance in meters (speed is m/s).
borderPolicy controls what happens when a node reaches the edge of the playground, and can take one of the values "reflect", "wrap", "placerandomly". In the first case, the node reflects off the wall; with "wrap", it'll come in on the other side (torus); and with "placerandomly", it will be placed at a random position on the playground.
In addition to the node position, the module maintains two interval variables, 'speed' and 'angle', which can be adjusted by <set> and <turn>. The <forward> statement, if only t or d is given, uses the speed variable. If you specify d and t together, that determines speed as well, so the speed variable will be ignored completely.
Likewise, <moveto> and <moveby> will ignore the angle variable, and will only use the speed variable if the t attribute is omitted.
If the repeat count n is omitted for the <repeat> statement, that means an infinite loop.
You can find the DTD with the sources: TurtleMobility.dtd.
See also: ChannelControl
Author: Andras Varga
The following diagram shows usage relationships between modules, networks and channels. Unresolved module (and channel) types are missing from the diagram. Click here to see the full picture.
describes the movement
time interval to update the hosts position
simple TurtleMobility parameters: coreDebug : bool, // debug switch debug : bool, // debug switch turtleScript: xml, // describes the movement updateInterval : numeric const; // time interval to update the hosts position endsimple