Input Determinism Sample Clauses
Input Determinism. If a set of input events in P are offered to the environment, none of them are refused. Formally, we say a process P is input deterministic if:
Input Determinism. The process does not use choices operator, hence the inputs offered are a full choice.
Input Determinism. If a set of input events in P are offered to the environment, none of them are refused. Formally, we say a process P is input deterministic if: – ∀ s ^ (c.a) : traces(P ) | c.a ∈ inputs(c, P ) • (s, {c.a}) ∈/ failures(P ) • Strong Output Decisive. All choices (if any) among output events on a given channel in P are internal. The process, however, must offer at least one output on that channel. Formally, we say a process is strong output decisive if: – ∀ s ^ (c.b) : traces(P ) | c.b ∈ outputs(c, P ) • (s, outputs(c, P )) ∈/ failures(P ) ∧ (s, outputs(c, P ) \ {c.b}) ∈ failures(P ) These conditions lay the foundations of our composition rules for contracts whenever every two components are compatible to interoperate. The appli- cation of the composition rules and the characterisation constraints in the component model impose side conditions that, if satisfied, ensure deadlock freedom in the composition result. Hence, in our approach, problems are anticipated before all parts are integrated. In [Ram11], we present four composition rules; each one focuses on a specific scenario at composition. The rules provide asynchronous pairwise compo- sitions and focus on the preservation of deadlock freedom in the resulting component. The preservation of livelock-freedom is not in the scope of this report but also discussed in [Ram11]. Using the rules, developers may syn- chronise two channels of two components, or even of the same component. The four rules are interleave, communication, feedback and reflexive compo- sitions. The first three rules have also been presented in [RSM09]. The interleave composition rule is the simplest form of composition. It ag- gregates two independent entities such that, after composition, these entities still do not communicate between themselves. They directly communicate with the environment as before, with no interference from each other. The only proviso states that they do not share any communication channel. • P and Q have disjoint channels, and; • CP ∩ CQ = ∅. Then, the interleave composition of P and Q (namely P [ |] Q) is given by: P [ |] Q = P() = ()Q This definition and others that follow use the direct composition operator = , which provides an asynchronous interaction, mediated by infinite buffers, between corresponding channels from two lists. In this rule, no channel participates in the operation. The result of an application of a composition rule is a new component. In many cases, it is necessary to provide a means to conn...
Input Determinism. The input choices are deterministic.
Input Determinism. In [RSM09], we formally define input determinism as follows: