Random Generation of bi-directional Graphs in Omnet :: Khyber.ORG

پښتو :: پښتانه :: پښتونخواه :: پښتونوالی

Random Generation of bi-directional Graphs in Omnet, Omar Usman
Published in Khyber.ORG on Wednesday, July 4 2012 (http://www.khyber.org)

New Additions

[an error occurred while processing this directive]

From Archives

خوشحال خان خټک ، احمد جان

خوشحال خان په پښتنو کښ د تکړه قام يعني د خټکو مشهور تورزن، جنګيالي او شاعر وۀ. په 1022 هجري (1613ء) کښ پيدا شوي وۀ. د دۀ پلار شهباز خان چه د پښتنو زورور قام يوسفزو سره جنګيدۀ هغي کښ زخمي شۀ او څو ورځې پس هم هغه پرهار نه مړ شۀ. د دۀ له مرګ پس خوشحال خان چه هغه هم دغه (د 1050هجري يا 1645ء په) جنګ کښ په سر او زنګون . . . نور

دتيرو پيړيو او صديو په اوږدو کښې دنړۍ په هيوادونو لويو لويو امپراتورانو حکومتونه کول ددوى واک حدود نۀ لرل هر څه چې به ددوى زړه غوښتل هغه به قانون و غريبو او مظلومو خلقو به دژوند حق هم نۀ درلود. دامپراتورانو او په دوى پورې دتړلو شتمنو کسانو اقتصادى ګتې به دلويو جنګونو او د نورو دولتونو . . . نور

Ajmal Khattak, a noted Pakistani Pushtun poet and politician, peacefully tried to help his people find their place in the sun. Now a refugee in Afghanistan, he seeks only peace but anticipates further violence... (An account of Ajmal Khattak written in 1976) . . . Read More

د پی ټی وي کوئټې څانګې ډرامه بېلتون ، فاروق سرور و حبيب پاني زئي

شائسته خان لېونئ شوې دې او نور د هغه زمکه جائداد ته غله دي . . . نور

Ghilzai : Iranica , Muhammad Jamil Hanifi

Ghilzi or Ghilzi (Pashto plural of singular masculine Ghilzai and singuler feminine Ghilzayi) are one of three major Pashtun tribal confederations in Afghanistan. The other two are the Durrani, formerly the Abdali, in western Afghanistan and the Karlani, who straddle the border between . . . Read More

Afridi : Iranica , C.M. Kieffer

Afridi or Apridi, designation of a major Pashtun tribe in northwest Pakistan, with a few members in Afghanistan. The Afridi form part of the Ghilzi and are thus of the so-called "eastern Pashtun," who are to be distinguished from the Dorrani encompassing the "western Pashtun." . . . Read More

Random Generation of bi-directional Graphs in Omnet

Omar Usman

Publishing Date: Wednesday, July 4 2012

The Omnet usman.html manual has code for generation of random topologies. The type of network generated can contain uni-directional, or bi-directional edges. Usually, people working with networks require generation of bi-directional graphs only. What you will see here is a small hack to the Omnet Engine, which can enable you to do that. (Note: I am not an expert on Omnet so most probably there is another simpler way of doing this. If you do, please leave a comment).

The files you need to modify are:

  1. src/sim/distrib.cc
  2. include/distrib.h
  3. src/sim/nedfunctions.cc

Modifications to distrib.cc

You need to create a new function (runiform). What this does is that it retains the random number generated from a previous call to uniform(). The random number is generated every 2-calls.

double runiform(int rng) {
static int r = 0;
static double l = 0;
if(r%2 == 0) l = uniform(0,1);
return l;

Modifications to distrib.h

Just one line to be modified here:

SIM_API double runiform(int rng=0);

Modifications to nedfunctions.cc

The current usman.html manual (July 4, 2012) shows a different way of doing this. The code in the manual is not consistent with what I found in the source (4.2.2). You need to add the following code to where the other continuous random variate generation code is present.

"quantity runiform(int rng?)",
"Retains the value generated from a previous call to uniform()",
int rng = argc==2 ? (int)argv[1] : 0;
return cNEDValue(runiform(rng), argv[0].getUnit());

Compilation and Usage

If you have already compiled omnet once, you can simply run make and compile the engine again. When complete, fire up your editor and open your .NED file. You can now generate bi-directional graphs using the following code from the manual (which is adopted to this hack):

module RandomGraph {
int count;
double connectedness; // 0.0 submodules:
node[count]: Node {
connections allowunconnected:
for i=0..count-1, for j=0..count-1 {
node[i].out[j] --> node[j].in[i]
if i<j && runiform() > connectedness;
node[j].out[i] --> node[i].in[j]
if i<j && runiform() > connectedness;

Comments powered by Disqus

Random Generation of bi-directional Graphs in Omnet, Omar Usman
Published in Khyber.ORG on Wednesday, July 4 2012 (http://www.khyber.org)