automathon 0.0.13

A Python library for simulating and visualizing finite automata

Automathon

Created by: Robin Hafid Quintero Lopez

A Python library for simulating and visualizing finite automata.

Links

• GitHub repository: https://github.com/rohaquinlop/automathon
• PyPI: https://pypi.org/project/automathon/
• Twitter: https://twitter.com/RobinHafid
• Contact: [e-mail]

Installation

PyPI

pip install automathon

You also need to install Graphviz on your computer (download page, installation procedure for Windows, archived versions).

Make sure that the directory containing the dot executable is on your systems’ path.

Upgrade

PyPI

pip install automathon --upgrade

Deterministic Finite Automata

Representing the previous automata

from automathon import DFA
Q = {'q0', 'q1', 'q2'}
sigma = {'0', '1'}
delta = { 'q0' : {'0' : 'q0', '1' : 'q1'},
          'q1' : {'0' : 'q2', '1' : 'q0'},
          'q2' : {'0' : 'q1', '1' : 'q2'}
        }
initialState = 'q0'
F = {'q0'}

automata1 = DFA(Q, sigma, delta, initialState, F)
## This is an example about creating a DFA with the library

Verify if the automata is valid

automata1.is_valid()  # True

Verify if the automata accept a string

automata1.accept("001001")   #True
automata1.accept("00100")    #False

Get the automata's complement

notautomata1 = automata1.complement()
notautomata1.accept("00100")    #True

Visualize the automata

For both, DFA and NFA, the view method enables to visualize the automaton, receives as parameter a String as the file name for the png and svg files.

More information about the graphviz attributes here.

automata1.view("DFA Visualization")

# Add custom styling

automata1.view(file_name="DFA Custom Styling",
               node_attr={'fontsize': '20'},
               edge_attr={'fontsize': '20pt'})

Convert DFA to NFA

If you need to use a DFA and operate with a NFA you can convert your DFA to NFA class, using the function getNFA. getNFA convert your DFA to NFA class and returns its conversion.

automata1NFA = automata1.get_nfa()
automata1NFA.view("DFA to NFA")

Product of two automatas

The product function receives a DFA and returns the product of two DFAs, your actual DFA and the given as parameter.

Q = {'A', 'B'}
sigma = {'0', '1'}
delta = {
  'A': {
    '0': 'A',
    '1': 'B'
  },
  'B': {
    '0': 'B',
    '1': 'A'
  }
}
initialState = 'A'
F = {'B'}
dfa = DFA(Q, sigma, delta, initialState, F)

Q1 = {'R', 'S', 'T', 'U'}
sigma1 = {'0', '1'}
delta1 = {
  'R': {
    '0': 'S',
    '1': 'R'
  },
  'S': {
    '0': 'T',
    '1': 'R'
  },
  'T': {
    '0': 'U',
    '1': 'R'
  },
  'U': {
    '0': 'U',
    '1': 'U'
  }
}
initialState1 = 'R'
F1 = {'U'}

dfa1 = DFA(Q1, sigma1, delta1, initialState1, F1)

dfa2 = dfa.product(dfa1)

assert dfa2.is_valid() == True
assert dfa2.accept("0001") == True
assert dfa2.accept("00010010") == False

Union of two automatas

The union function receives a DFA and returns the union of two DFAs, your actual DFA and the given as parameter.

Q = {'A', 'B'}
sigma = {'0', '1'}
delta = {
  'A': {
    '0': 'A',
    '1': 'B'
  },
  'B': {
    '0': 'B',
    '1': 'A'
  }
}
initialState = 'A'
F = {'B'}
dfa = DFA(Q, sigma, delta, initialState, F)

Q1 = {'R', 'S', 'T', 'U'}
sigma1 = {'0', '1'}
delta1 = {
  'R': {
    '0': 'S',
    '1': 'R'
  },
  'S': {
    '0': 'T',
    '1': 'R'
  },
  'T': {
    '0': 'U',
    '1': 'R'
  },
  'U': {
    '0': 'U',
    '1': 'U'
  }
}
initialState1 = 'R'
F1 = {'U'}

dfa1 = DFA(Q1, sigma1, delta1, initialState1, F1)

dfa2 = dfa.union(dfa1)

assert dfa2.accept("00010010") == True
assert dfa2.accept("0011000") == True
assert dfa.is_valid() == True

Non-Deterministic Finite Automata

Image taken from: http://www.r9paul.org/blog/2008/nondeterministic-finite-state-machine/

Representing the previous automata

from automathon import NFA

## Epsilon Transition is denoted by '' -> Empty string
Q = {'q1', 'q2', 'q3', 'q4'}
sigma = {'0', '1'}
delta = {
          'q1' : {
                  '0' : {'q1'},
                  '1' : {'q1', 'q2'}
                  },
          'q2' : {
                  '0' : {'q3'},
                  '' : {'q3'}
                  },
          'q3' : {
                  '1' : {'q4'},
                  },
          'q4' : {
                  '0' : {'q4'},
                  '1' : {'q4'},
                  },
        }
initialState = 'q1'
F = {'q4'}

automata2 = NFA(Q, sigma, delta, initialState, F)
## This is an example about creating a NFA with the library

Verify if the automata is valid

automata2.is_valid()  # True

Verify if the automata accept a string

automata2.accept("0000011")   #True
automata2.accept("000001")    #False

Get the automata's complement

notautomata2 = automata1.complement()
notautomata2.accept("000001")    #True

Visualize the automata

automata2.view("NFA Visualization")

# Add custom styling

automata2.view(file_name="NFA Custom Styling",
               node_attr={'fontsize': '20'},
               edge_attr={'fontsize': '20pt'})

Remove Epsilon transitions from NFA

automata3 = automata2.remove_epsilon_transitions()
automata3.view("NFA without EpsilonTransitions")

Convert NFA to DFA

automata4 = automata3.get_dfa()
automata4.view("NFA to DFA")

Product of two automatas

The product function receives a NFA and returns the product of two NFAs, your actual NFA and the given as parameter.

Q = {'A', 'B'}
sigma = {'a', 'b'}
delta = {
  'A': {
    'a': {'B'},
    'b': {'A'}
  },
  'B': {
    'a': {'A'},
    'b': {'B'}
  }
}
initialState = 'A'
F = {'A'}

nfa = NFA(Q, sigma, delta, initialState, F)

Q1 = {'C', 'D'}
sigma1 = {'a', 'b'}
delta1 = {
  'C': {
    'a': {'C'},
    'b': {'D'}
  },
  'D': {
    'a': {'D'},
    'b': {'C'}
  }
}
initialState1 = 'C'
F1 = {'C'}

nfa1 = NFA(Q1, sigma1, delta1, initialState1, F1)

nfa2 = nfa.product(nfa1)

assert nfa2.is_valid() == True
assert nfa2.accept('') == True
assert nfa2.accept('bb') == True
assert nfa2.accept('b') == False
assert nfa2.accept('bbaa') == True
assert nfa2.accept('bbaaa') == False

Union of two automatas

The union function receives a NFA and returns the union of two NFAs, your actual NFA and the given as parameter.

Q = {'A'}
sigma = {'a'}
delta = {
  'A': {
    'a': {'A'}
  }
}
initialState = 'A'
F = {'A'}
nfa = NFA(Q, sigma, delta, initialState, F)

Q1 = {'C', 'D', 'E'}
sigma1 = {'a', 'b'}
delta1 = {
  'C': {
    'b': {'D'},
  },
  'D': {
    'a': {'E'},
    'b': {'D'}
  }
}

initialState1 = 'C'
F1 = {'E'}

nfa1 = NFA(Q1, sigma1, delta1, initialState1, F1)

nfa2 = nfa.union(nfa1)

assert nfa2.is_valid() == True
assert nfa2.accept("aaaaaa") == True
assert nfa2.accept("aaaabbbbaaa") == False
assert nfa2.accept("bbbbbbbbba") == True
assert nfa2.accept("aaaaaaaab") == False

Errors

Errors that can be returned during the execution, and the cases that can appear.

• SigmaError:

  • The automata contain an initial state, or a final state that's not defined on Q.
  • The automata contain a delta transition that's not defined on Q or in Sigma.

• InputError:

  • The automata is trying to consume a letter that's not defined in sigma.