Example 2 p
Example p2 t1 p1 t2 p4 t3 p3
Definition of petri net C=(P,T,L,O) o Places P={p,p2,p3,…,pn} Transitions T={t1,t2,t3,…,tn} o Input I: T>P(r= number of places).t Output pl O: T>Pq(q= number of places 12
Definition of Petri Net ◼ C = ( P, T, I, O) Places P = { p1 , p2 , p3 , …, pn} Transitions T = { t1 , t2 , t3 , …, tn} Input I : T → P r (r = number of places) •t Output O : T → P q (q = number of places) t • 12
marking u: assignment of tokens to the places of Petri net 2 t2 p t3 13
◼ marking µ : assignment of tokens to the places of Petri net µ = µ1 , µ2 , µ3 , … µn 13 p2 t1 p1 t2 p4 t3 p3
Applications performance evaluation communication protocols distributed-software systems distributed-database systems concurrent and parallel programs industrial control systems discrete-events systems multiprocessor memory systems dataflow-computing systems fault-tolerant systems etc etc. etc
Applications ◼ performance evaluation ◼ communication protocols ◼ distributed-software systems ◼ distributed-database systems ◼ concurrent and parallel programs ◼ industrial control systems ◼ discrete-events systems ◼ multiprocessor memory systems ◼ dataflow-computing systems ◼ fault-tolerant systems ◼ etc, etc, etc
Basics of petri nets Petri net consist two types of nodes: places and transitions. And arc exists only from a place to a transition or from a transition to a place a place may have zero or more tokens Graphically, places, transitions, arcs, and tokens are represented respectively by: circles, bars, arrows and dots Below is an example petri net with two places and one transaction 15
Basics of Petri Nets ◼ Petri net consist two types of nodes: places and transitions. And arc exists only from a place to a transition or from a transition to a place. ◼ A place may have zero or more tokens. ◼ Graphically, places, transitions, arcs, and tokens are represented respectively by: circles, bars, arrows, and dots. ◼ Below is an example Petri net with two places and one transaction. p 15 p1 2 t1