Fault Tolerance provided by Capillary Routing

 

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Description of the AMPL code

 

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Building the random walk network

 

..\a21download\randomwalk.txt

Script

Comments

printf "Preparing the timeframes of random walk ad-hoc network:\n";

for{i in NODES}

{

  let xx[i] := Uniform(0,x_max);

  let yy[i] := Uniform(0,y_max);

  let x[1,i] := xx[i];

  let y[1,i] := yy[i];

}

◄Initializing the coordinates of the first timeframe

printf "  (1) Positions of nodes evolving over time ... ";

for{t in 2..T}

{

◄the loop of frames starting from the second timeframe

  for{i in NODES}

  {

◄loop for each node

    if 0 <= Uniform(0,walk) <= step

      then let a[i] := Uniform(0,2*PI);

◄if it is a time for a turn, randomly change the direction of the node

    repeat

    {

      let xxx := xx[i]+step*cos(a[i]);

      let yyy := yy[i]+step*sin(a[i]);

◄compute the next position of the node

      if xxx in interval [0,x_max] && yyy in interval [0,y_max]

        then break;

      let a[i] := Uniform(0,2*PI);

    }

◄if the next position of the node is not in the allowed rectangular area, change randomly the direction of the node and retry

    let xx[i] := xxx;

    let yy[i] := yyy;

  }

◄store the new valid coordinates of the node

  for{i in NODES}

  {

    let x[t,i] := xx[i];

    let y[t,i] := yy[i];

  }

◄save under the index of the current timeframe the coordinates of all nodes

}

printf "Ok\n";

◄close the loop of timeframes

printf "  (2) Adding links ... ";

◄computing the links

for{t in 1..T}

  let LINKS[t] :=

    union{i in 1..N, j in i+1..N: (x[t,i]-x[t,j])^2+(y[t,i]-y[t,j])^2<=r^2}

      {(i,j), (j,i)};

◄for each pair of nodes (a pair is considered only once) we add two arcs of opposite directions (symmetric directed graph) if the geometrical distance between the nodes is less or equal the coverage radius of the node

printf "Ok\n";

printf "Done.\n\n";

◄end of the construction of the random walk network

 

 

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