State space visualization examples

(This page is under construction)

Alternating Bit Protocol

This is a visualisation of 3643 states and 11115 transitions of a TLA+ model of the alternating bit protocol, as distributed with the TLA+ tools. This model (MCAlternatingBit.tla) was loaded with ProB for TLA+, the model checker run for a few seconds and then the command "State Space Fast Rendering" with options (scale,fast) was used.

The goal predicate rBit=1 was used; those states satisfying this predicate are shown in orange.

Below is a projection of this state space onto the expression (rBit,sBit), using the "Custom Transition Diagram" feature of ProB:

More details about this statespace projection feature can be found in our ICFEM'15 article.

The main file of the model is:

--------------------------- MODULE MCAlternatingBit -------------------------
EXTENDS AlternatingBit, TLC

INSTANCE ABCorrectness 

CONSTANTS msgQLen, ackQLen

SeqConstraint == /\ Len(msgQ) \leq msgQLen
                 /\ Len(ackQ) \leq ackQLen

SentLeadsToRcvd == \A d \in Data : (sent = d) /\ (sBit # sAck) ~> (rcvd = d)
=============================================================================

ImpliedAction == [ABCNext]_cvars

TNext == WF_msgQ(~ABTypeInv')
TProp == \A d \in Data : (sent = d) => [](sent = d)

CSpec == ABSpec /\ TNext

DataPerm == Permutations(Data)
==============================================================

MCInnerFIFO

This is a visualisation of 5081 states and 7569 transitions of a TLA+ model of a FIFO, as distributed with the TLA+ tools. This model (MCAlternatingBit.tla) was loaded with ProB for TLA+, the model checker run for a few seconds and then the command "State Space Fast Rendering" with options (scale,fast) was used.

The colour indicates the length of the queue variable q of the model (gray=0,blue=1,red=2, green=3) .