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<<<<<<< HEAD // synchronous leader election protocol (itai & Rodeh) // dxp/gxn 25/01/01
dtmc
// CONSTANTS const int N = 5; // number of processes const int K = 8; // range of probabilistic choice
// counter module used to count the number of processes that have been read // and to know when a process has decided module counter // counter (c=i means process j reading process (i-1)+j next) c : [1..N-1]; // reading [read] c<N-1 -> (c'=c+1); // finished reading [read] c=N-1 -> (c'=c); //decide [done] u1|u2|u3|u4|u5 -> (c'=c); // pick again reset counter [retry] !(u1|u2|u3|u4|u5) -> (c'=1); // loop (when finished to avoid deadlocks) [loop] s1=3 -> (c'=c); endmodule
// processes form a ring and suppose: // process 1 reads process 2 // process 2 reads process 3 // process 3 reads process 1 module process1 // local state s1 : [0..3]; // s1=0 make random choice // s1=1 reading // s1=2 deciding // s1=3 finished // has a unique id so far (initially true) u1 : bool; // value to be sent to next process in the ring (initially sets this to its own value) v1 : [0..K-1]; // random choice p1 : [0..K-1]; // pick value [pick] s1=0 -> 1/K : (s1'=1) & (p1'=0) & (v1'=0) & (u1'=true) + 1/K : (s1'=1) & (p1'=1) & (v1'=1) & (u1'=true) + 1/K : (s1'=1) & (p1'=2) & (v1'=2) & (u1'=true) + 1/K : (s1'=1) & (p1'=3) & (v1'=3) & (u1'=true) + 1/K : (s1'=1) & (p1'=4) & (v1'=4) & (u1'=true) + 1/K : (s1'=1) & (p1'=5) & (v1'=5) & (u1'=true) + 1/K : (s1'=1) & (p1'=6) & (v1'=6) & (u1'=true) + 1/K : (s1'=1) & (p1'=7) & (v1'=7) & (u1'=true); // read [read] s1=1 & u1 & c<N-1 -> (u1'=(p1!=v2)) & (v1'=v2); [read] s1=1 & !u1 & c<N-1 -> (u1'=false) & (v1'=v2) & (p1'=0); // read and move to decide [read] s1=1 & u1 & c=N-1 -> (s1'=2) & (u1'=(p1!=v2)) & (v1'=0) & (p1'=0); [read] s1=1 & !u1 & c=N-1 -> (s1'=2) & (u1'=false) & (v1'=0); // deciding // done [done] s1=2 -> (s1'=3) & (u1'=false) & (v1'=0) & (p1'=0); //retry [retry] s1=2 -> (s1'=0) & (u1'=false) & (v1'=0) & (p1'=0); // loop (when finished to avoid deadlocks) [loop] s1=3 -> (s1'=3); endmodule
// construct remaining processes through renaming module process2 = process1 [ s1=s2,p1=p2,v1=v2,u1=u2,v2=v3 ] endmodule module process3 = process1 [ s1=s3,p1=p3,v1=v3,u1=u3,v2=v4 ] endmodule module process4 = process1 [ s1=s4,p1=p4,v1=v4,u1=u4,v2=v5 ] endmodule module process5 = process1 [ s1=s5,p1=p5,v1=v5,u1=u5,v2=v1 ] endmodule
// expected number of rounds rewards "num_rounds" [pick] true : 1; endrewards
// labels label "elected" = s1=3&s2=3&s3=3&s4=3&s5=3;
======= // synchronous leader election protocol (itai & Rodeh) // dxp/gxn 25/01/01
dtmc
// CONSTANTS const int N = 5; // number of processes const int K = 8; // range of probabilistic choice
// counter module used to count the number of processes that have been read // and to know when a process has decided module counter // counter (c=i means process j reading process (i-1)+j next) c : [1..N-1]; // reading [read] c<N-1 -> (c'=c+1); // finished reading [read] c=N-1 -> (c'=c); //decide [done] u1|u2|u3|u4|u5 -> (c'=c); // pick again reset counter [retry] !(u1|u2|u3|u4|u5) -> (c'=1); // loop (when finished to avoid deadlocks) [loop] s1=3 -> (c'=c); endmodule
// processes form a ring and suppose: // process 1 reads process 2 // process 2 reads process 3 // process 3 reads process 1 module process1 // local state s1 : [0..3]; // s1=0 make random choice // s1=1 reading // s1=2 deciding // s1=3 finished // has a unique id so far (initially true) u1 : bool; // value to be sent to next process in the ring (initially sets this to its own value) v1 : [0..K-1]; // random choice p1 : [0..K-1]; // pick value [pick] s1=0 -> 1/K : (s1'=1) & (p1'=0) & (v1'=0) & (u1'=true) + 1/K : (s1'=1) & (p1'=1) & (v1'=1) & (u1'=true) + 1/K : (s1'=1) & (p1'=2) & (v1'=2) & (u1'=true) + 1/K : (s1'=1) & (p1'=3) & (v1'=3) & (u1'=true) + 1/K : (s1'=1) & (p1'=4) & (v1'=4) & (u1'=true) + 1/K : (s1'=1) & (p1'=5) & (v1'=5) & (u1'=true) + 1/K : (s1'=1) & (p1'=6) & (v1'=6) & (u1'=true) + 1/K : (s1'=1) & (p1'=7) & (v1'=7) & (u1'=true); // read [read] s1=1 & u1 & c<N-1 -> (u1'=(p1!=v2)) & (v1'=v2); [read] s1=1 & !u1 & c<N-1 -> (u1'=false) & (v1'=v2) & (p1'=0); // read and move to decide [read] s1=1 & u1 & c=N-1 -> (s1'=2) & (u1'=(p1!=v2)) & (v1'=0) & (p1'=0); [read] s1=1 & !u1 & c=N-1 -> (s1'=2) & (u1'=false) & (v1'=0); // deciding // done [done] s1=2 -> (s1'=3) & (u1'=false) & (v1'=0) & (p1'=0); //retry [retry] s1=2 -> (s1'=0) & (u1'=false) & (v1'=0) & (p1'=0); // loop (when finished to avoid deadlocks) [loop] s1=3 -> (s1'=3); endmodule
// construct remaining processes through renaming module process2 = process1 [ s1=s2,p1=p2,v1=v2,u1=u2,v2=v3 ] endmodule module process3 = process1 [ s1=s3,p1=p3,v1=v3,u1=u3,v2=v4 ] endmodule module process4 = process1 [ s1=s4,p1=p4,v1=v4,u1=u4,v2=v5 ] endmodule module process5 = process1 [ s1=s5,p1=p5,v1=v5,u1=u5,v2=v1 ] endmodule
// expected number of rounds rewards "num_rounds" [pick] true : 1; endrewards
// labels label "elected" = s1=3&s2=3&s3=3&s4=3&s5=3;
>>>>>>> 90d2b218a044edca8062084ee89d171695149c1e
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