Contents

Causality view

When the Causality view check-box on the Animation Control window is chosen, the Causality view will pop up.

Figure 8: Causality view of experiment Broadcast with ACK 

The causality view shows the causal relations of the algorithm. A relation is shown in the form of an arrow pointing from sender to receiver of a message beginning at and ending at. Hereby denotes the local clock of the sender when it sent the message, while denotes the local clock of the receiver when receiving the message. The local clock of a process is updated when a message was sent or received. Before sending a message a process increases its local clock by one, while receiving a message causes a process to set its local clock to

$$new~clock~value = max(old~clock~value, received~clock~value)+1.$$ (1)

The causal relations are coloured according to a local colour value. Initially this value is 0 for all processes. The local colour value of a process is updated when a message is received.

2002-11-11