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38 lines
911 B
38 lines
911 B
// Israeli-Jalfon self stabilising algorithm
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// dxp/gxn 10/06/02
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mdp
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// variables to represent whether a process has a token or not
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// note they are global because they can be updated by other processes
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global q1 : [0..1];
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global q2 : [0..1];
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global q3 : [0..1];
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// module of process 1
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module process1
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[] (q1=1) -> 0.5 : (q1'=0) & (q3'=1) + 0.5 : (q1'=0) & (q2'=1);
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endmodule
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// add further processes through renaming
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module process2 = process1 [ q1=q2, q2=q3, q3=q1 ] endmodule
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module process3 = process1 [ q1=q3, q2=q1, q3=q2 ] endmodule
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// cost - 1 in each state (expected steps)
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rewards "steps"
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true : 1;
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endrewards
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// formula, for use here and in properties: number of tokens
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formula num_tokens = q1+q2+q3;
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// label - stable configurations (1 token)
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label "stable" = num_tokens=1;
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// initial states (at least one token)
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init
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num_tokens >= 1
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endinit
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