# -*- coding: utf-8 -*-
#+TITLE: =randaut=
#+DESCRIPTION: Spot command-line tool for generating random ω-automata.
#+SETUPFILE: setup.org
#+HTML_LINK_UP: tools.html
The =randaut= tool generates random (connected) automata.
By default, it will generate a random automaton with 10 states, no
acceptance sets, and using a set of atomic propositions you have to
supply.
#+NAME: randaut1
#+BEGIN_SRC sh :results verbatim :exports code
randaut a b --dot
#+END_SRC
#+RESULTS: randaut1
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label=<0>]
0 -> 8 [label=]
0 -> 3 [label=]
0 -> 4 [label=]
1 [label=<1>]
1 -> 7 [label=]
1 -> 0 [label=]
1 -> 6 [label=]
2 [label=<2>]
2 -> 4 [label=]
2 -> 0 [label=]
2 -> 5 [label=]
2 -> 9 [label=]
3 [label=<3>]
3 -> 2 [label=]
3 -> 9 [label=]
3 -> 3 [label=]
4 [label=<4>]
4 -> 0 [label=]
4 -> 7 [label=]
5 [label=<5>]
5 -> 3 [label=]
5 -> 1 [label=]
5 -> 7 [label=]
5 -> 9 [label=]
5 -> 5 [label=]
6 [label=<6>]
6 -> 8 [label=]
6 -> 5 [label=]
6 -> 2 [label=]
7 [label=<7>]
7 -> 8 [label=]
7 -> 9 [label=]
7 -> 0 [label=]
7 -> 1 [label=]
7 -> 4 [label=]
8 [label=<8>]
8 -> 1 [label=]
8 -> 3 [label=]
9 [label=<9>]
9 -> 1 [label=]
9 -> 3 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut1.png :cmdline -Tpng :var txt=randaut1 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut1.png]]
As for [[file:randltl.org][=randltl=]], you can supply a number of atomic propositions
instead of giving a list of atomic propositions.
* States and density
The numbers of states can be controlled using the =-Q= option. This
option will accept a range as argument, so for instance =-Q3..6= will
generate an automaton with 3 to 6 states.
The number of edges can be controlled using the =-e= (or
=--density=) option. The argument should be a number between 0 and 1.
In an automaton with $Q$ states and density $e$, the degree of each
state will follow a normal distribution with mean $1+(Q-1)d$ and
variance $(Q-1)e(1-e)$.
In particular =-e0= will cause all states to have 1 successors, and
=-e1= will cause all states to be interconnected.
#+NAME: randaut2
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q3 -e0 2 --dot
#+END_SRC
#+RESULTS: randaut2
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label=<0>]
0 -> 2 [label=]
1 [label=<1>]
1 -> 1 [label=]
2 [label=<2>]
2 -> 1 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut2.png :cmdline -Tpng :var txt=randaut2 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut2.png]]
#+NAME: randaut3
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q3 -e1 2 --dot
#+END_SRC
#+RESULTS: randaut3
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label=<0>]
0 -> 2 [label=]
0 -> 0 [label=]
0 -> 1 [label=]
1 [label=<1>]
1 -> 1 [label=]
1 -> 2 [label=]
1 -> 0 [label=]
2 [label=<2>]
2 -> 1 [label=]
2 -> 0 [label=]
2 -> 2 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut3.png :cmdline -Tpng :var txt=randaut3 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut3.png]]
* Acceptance condition
The generation of the acceptance sets abn is controlled with the following four parameters:
- =-A ACCEPTANCE= (or =--acceptance=ACCEPTANCE=) controls both the acceptance condition,
and the number of associated acceptance sets. The =ACCEPTANCE= argument is documented
in =--help= as follows:
#+BEGIN_SRC sh :results verbatim :exports results
randaut --help | sed -n '/^ \(ACCEPTANCE\|RANGE\)/,/^$/p'
#+END_SRC
#+RESULTS:
#+begin_example
RANGE may have one of the following forms: 'INT', 'INT..INT', or '..INT'.
In the latter case, the missing number is assumed to be 1.
ACCEPTANCE may be either a RANGE (in which case generalized Büchi is
assumed), or an arbitrary acceptance formula such as 'Fin(0)|Inf(1)&Fin(2)' in
the same syntax as in the HOA format, or one of the following patterns:
none
all
Buchi
co-Buchi
generalized-Buchi RANGE
generalized-co-Buchi RANGE
Rabin RANGE
Streett RANGE
generalized-Rabin INT RANGE RANGE ... RANGE
parity (min|max|rand) (odd|even|rand) RANGE
random RANGE
random RANGE PROBABILITY
The random acceptance condition uses each set only once, unless a probability
(to reuse the set again every time it is used) is given.
#+end_example
When a range of the form $i..j$ is used, the actual value is taken as randomly
between $i$ and $j$ (included).
- =-a= (or =--acc-probability=) controls the probability that any
transition belong to a given acceptance set.
- =-S= (or =--state-based-acceptance=) requests that the automaton
use state-based acceptance. In this case, =-a= is the probability
that a /state/ belong to the acceptance set. (Because Spot only
deals with transition-based acceptance internally, this options
force all transitions leaving a state to belong to the same
acceptance sets. But if the output format allows state-based
acceptance, it will be used.)
- =--colored= requests that each transition (of state if combined with =-S=)
in the generated automaton should belong to exactly one set (in that
case =-a= is ignored, and =-A= must be used to specify an acceptance
condition with at least one set).
In addition, =-B= (or =--ba=) is a shorthand for =-A1 -S=,
ans =-s= (or =--spin=) implies =-B=.
#+NAME: randaut4
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q3 -e0.5 -A3 -a0.5 2 --dot
#+END_SRC
#+RESULTS: randaut4
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label="0"]
0 -> 1 [label=]
0 -> 0 [label=❷>]
1 [label="1"]
1 -> 1 [label=⓿❶>]
1 -> 2 [label=❶>]
2 [label="2"]
2 -> 1 [label=⓿>]
2 -> 0 [label=⓿>]
2 -> 2 [label=⓿>]
}
#+end_example
#+BEGIN_SRC dot :file randaut4.png :cmdline -Tpng :var txt=randaut4 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut4.png]]
#+NAME: randaut5
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q3 -e0.4 -B -a0.7 2 --dot
#+END_SRC
#+RESULTS: randaut5
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label="0"]
0 -> 1 [label=]
0 -> 2 [label=]
1 [label="1", peripheries=2]
1 -> 1 [label=]
1 -> 0 [label=]
2 [label="2", peripheries=2]
2 -> 0 [label=]
2 -> 2 [label=]
2 -> 1 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut5.png :cmdline -Tpng :var txt=randaut5 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut5.png]]
#+NAME: randaut5b
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q6 -e0.4 -S -a.2 -A 'Streett 1..3' 2 --dot=.a
#+END_SRC
#+RESULTS: randaut5b
#+begin_example
digraph G {
rankdir=LR
label=<(Fin(⓿) | Inf(❶)) & (Fin(❷) | Inf(❸))>
labelloc="t"
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label=<0>]
0 -> 2 [label=]
0 -> 1 [label=]
0 -> 3 [label=]
1 [label=<1>]
1 -> 5 [label=]
2 [label=<2
⓿❷>]
2 -> 1 [label=]
2 -> 2 [label=]
2 -> 4 [label=]
3 [label=<3>]
3 -> 2 [label=]
3 -> 3 [label=]
4 [label=<4>]
4 -> 0 [label=]
4 -> 5 [label=]
5 [label=<5
❶❷>]
5 -> 1 [label=]
5 -> 2 [label=]
5 -> 3 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut5b.png :cmdline -Tpng :var txt=randaut5b :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut5b.png]]
For generating random parity automata you should use the option
=--colored= to make sure each transition (or state in the following
example) belong to exactly one acceptance set. Note that you can
specify a precise parity acceptance such as =parity min even 3=, or
give =randaut= some freedom, as in this example.
#+NAME: randaut5c
#+BEGIN_SRC sh :results verbatim :exports code
randaut -Q10 -S --colored -A 'parity rand rand 3..4' 2 --dot=.a
#+END_SRC
#+RESULTS: randaut5c
#+begin_example
digraph G {
rankdir=LR
label=⓿) | (Fin(❶) & (Inf(❷) | Fin(❸)))>
labelloc="t"
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label=<0
❶>]
0 -> 2 [label=]
0 -> 8 [label=]
0 -> 0 [label=]
0 -> 6 [label=]
1 [label=<1
❸>]
1 -> 5 [label=]
1 -> 9 [label=]
2 [label=<2
❷>]
2 -> 4 [label=]
2 -> 5 [label=]
3 [label=<3
⓿>]
3 -> 6 [label=]
3 -> 1 [label=]
4 [label=<4
⓿>]
4 -> 6 [label=]
4 -> 1 [label=]
5 [label=<5
⓿>]
5 -> 0 [label=]
5 -> 8 [label=]
5 -> 7 [label=]
6 [label=<6
⓿>]
6 -> 2 [label=]
6 -> 3 [label=]
7 [label=<7
❷>]
7 -> 3 [label=]
7 -> 1 [label=]
8 [label=<8
⓿>]
8 -> 3 [label=]
8 -> 4 [label=]
8 -> 2 [label=]
8 -> 0 [label=]
9 [label=<9
❶>]
9 -> 0 [label=]
9 -> 6 [label=]
}
#+end_example
#+BEGIN_SRC dot :file randaut5c.png :cmdline -Tpng :var txt=randaut5c :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut5c.png]]
* Determinism
The output can only contain a single edge between two given states.
By default, the label of this edge is a random assignment of all
atomic propositions. Two edges leaving the same state may therefore
have the same label.
If the =-D= (or =--deterministic=) option is supplied, the labels
are generated differently: once the degree $m$ of a state has been
decided, the algorithm will compute a set of $m$ disjoint
Boolean formulas over the given atomic propositions, such that the
sum of all these formulas is $\top$. The resulting automaton is
therefore deterministic and complete.
#+NAME: randaut6
#+BEGIN_SRC sh :results verbatim :exports code
randaut -D -Q3 -e0.6 -A2 -a0.5 2 --dot
#+END_SRC
#+RESULTS: randaut6
#+begin_example
digraph G {
rankdir=LR
node [shape="circle"]
fontname="Lato"
node [fontname="Lato"]
edge [fontname="Lato"]
node[style=filled, fillcolor="#ffffa0"] edge[arrowhead=vee, arrowsize=.7]
I [label="", style=invis, width=0]
I -> 0
0 [label="0"]
0 -> 1 [label=]
0 -> 2 [label=]
1 [label="1"]
1 -> 2 [label=❶>]
1 -> 0 [label=⓿>]
2 [label="2"]
2 -> 2 [label=⓿>]
2 -> 0 [label=❶>]
2 -> 1 [label=⓿>]
}
#+end_example
#+BEGIN_SRC dot :file randaut6.png :cmdline -Tpng :var txt=randaut6 :exports results
$txt
#+END_SRC
#+RESULTS:
[[file:randaut6.png]]
Note that in a deterministic automaton with $a$ atomic propositions,
it is not possible to have states with more than $2^a$ successors. If
the combination of =-e= and =-Q= allows the situation where a state
can have more than $2^a$ successors, the degree will be clipped to
$2^a$. When working with random deterministic automata over $a$
atomic propositions, we suggest you always request more than $2^a$
states.
* Output formats
The output format can be controlled using [[file:oaut.org][the common output options]]
like =--hoaf=, =--dot==, =--lbtt=, and =--spin=. Note that =--spin=
automatically implies =--ba=.
* Generating a stream of automata
Use option =-n= to specify a number of automata to build. A negative
value will cause an infinite number of automata to be produced. This
generation of multiple automata is useful when piped to another tool
that can process automata in batches.