275 lines
8.5 KiB
Python
275 lines
8.5 KiB
Python
"""A small module to express formulas and write them in SMTLIB2,
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Marabou input format, PyRAT input format. Conjunction of linear constraints,
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with logical operators if necessary"""
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from fractions import Fraction
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import re
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DIST = 'x0'
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SPEED = 'x1'
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ANGLE = 'x2'
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OUTPUT = 'y0'
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GEQ = '>='
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GQ = '>'
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LT = '<'
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AND = 'and'
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OR = 'or'
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class Atom():
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"""A basic atom for a formula"""
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def __init__(self):
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self.var = None
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self.real = None
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def is_real(self):
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return self.real is not None
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def is_var(self):
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return self.var is not None
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class Real(Atom):
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"""A real number"""
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def __init__(self, x):
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super(Real, self).__init__()
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if isinstance(x, (float, int)):
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self.real = x
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else:
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print('Error, Real can only be of int or float')
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raise ValueError
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def __str__(self):
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return str(self.real)
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def to_smtlib(self):
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frac = Fraction(self.real)
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return '(/ {} {})'.format(frac.numerator, frac.denominator)
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def to_marabou(self):
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return ' {} '.format(self.real)
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def to_pyrat(self):
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return ' {} '.format(self.real)
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class Var(Atom):
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"""A variable with a name"""
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def __init__(self, x):
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super(Var, self).__init__()
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if isinstance(x, str):
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if re.search("^[xy][0-9]$", x):
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self.var = x
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else:
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raise ValueError("Input should be of the form x[0-9] or y[0-9]")
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else:
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raise ValueError("Input should be of the form x[0-9] or y[0-9]")
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def __str__(self):
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return str(self.var)
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def to_smtlib(self):
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if self.var == DIST:
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return '|CELL_actual_input_0_0_0|'
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elif self.var == SPEED:
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return'|CELL_actual_input_0_0_1|'
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elif self.var == ANGLE:
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return'|CELL_actual_input_0_0_2|'
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else: # only remaining is Output
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return '|CELL_actual_output_0_0_0|'
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def to_marabou(self):
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return self.var
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def to_pyrat(self):
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return self.var
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class Constr():
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"""A linear constraint"""
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def __init__(self, a, bop, b):
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"""a and b are atoms, bop is either '>=' or '<'"""
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if not (isinstance(a, Atom) and isinstance(b, Atom)):
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print('Error, either a or b are not atoms. \
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Create atoms using Var or Real constructors.')
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raise ValueError
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else:
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if bop == GEQ or bop == LT:
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self.constr = (a, bop, b)
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else:
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print('Error, second argument should be either >= or <')
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raise ValueError
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def __str__(self):
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a, bop, b = self.constr
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return '{} {} {}'.format(str(a), bop, str(b))
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def to_smtlib(self):
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"""write a constraint to SMTLIB format"""
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a, bop, b = self.constr
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if "y" in str(a) or "y" in str(b):
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bop = GEQ if bop == LT else LT
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return '({} {} {})'.format(bop, a.to_smtlib(), b.to_smtlib())
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def to_marabou(self):
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"""write a constraint to marabou format"""
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a, bop, b = self.constr
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if "y" in str(a) or "y" in str(b):
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bop = GEQ if bop == LT else LT
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if bop == GEQ:
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return '{} {} {}'.format(a.to_marabou(), bop, b.to_marabou())
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else:
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# print('Warning: Marabou does not support strict inequality, \
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# using Lower or Equal ( <= ) instead')
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return '{} {} {}'.format(a.to_marabou(), '<=', b.to_marabou())
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def to_pyrat(self):
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a, bop, b = self.constr
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return '{} {} {}'.format(a.to_pyrat(), bop, b.to_pyrat())
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def well_formed(c):
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"""Check if c is a well formed clause"""
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if len(c) == 3:
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cx = c[0]
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lop = c[1]
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cy = c[2]
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if lop in (AND, OR):
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return isinstance(cx, Constr) and isinstance(cy, Constr)
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else:
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print('Error, second argument should be AND | OR')
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return False
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class Formula():
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"""A formula composed of a conjunction of constraints"""
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def __init__(self):
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"""A formula is empty at the beginning"""
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self.storage = []
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def __str__(self):
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to_display = ''
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for clause in self.storage:
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if isinstance(clause, Constr):
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to_display += '{}; '.format(str(clause))
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else:
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cx, lop, cy = clause
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to_display += '({} {} {}); '.format(str(cx), str(lop),
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str(cy))
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return to_display
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def add(self, c):
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"""Add a disjunction to the formula with the constr"""
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if isinstance(c, Constr):
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self.storage.append(c)
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elif well_formed(c):
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self.storage.append((c[0], c[1], c[2]))
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else:
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print('Error, input must either be an instance of Constr or \
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a tuple (formula, AND|OR, constr)')
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def to_smtlib(self):
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"""Write down the formula to SMTLIB format"""
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to_write = ''
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for clause in self.storage:
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if isinstance(clause, Constr):
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tmp = clause.to_smtlib()
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else:
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cx, lop, cy = clause
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tmp = '({} {} {})'.format(
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str(lop), cx.to_smtlib(), cy.to_smtlib())
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to_write += '(assert {})\n'.format(tmp)
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return to_write
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def to_marabou(self):
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"""Write down the formula to Marabou format"""
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to_write = ''
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for clause in self.storage:
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if isinstance(clause, Constr):
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to_write += '{}\n'.format(clause.to_marabou())
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else:
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# Marabou only deal with AND logical operators
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cx, lop, cy = clause
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if lop == AND:
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to_write += '{}\n'.format(cx.to_marabou())
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to_write += '{}\n'.format(cy.to_marabou())
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else:
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print('Error, Marabou output format does not support \
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OR operator. Aborting conversion.')
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raise ValueError
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return to_write
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def to_pyrat(self):
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"""Write down the formula to PyRAT format"""
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to_write = ''
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for clause in self.storage:
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if isinstance(clause, Constr):
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to_write += '{}\n'.format(clause.to_pyrat())
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else:
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# PyRAT only deal with AND logical operators
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cx, lop, cy = clause
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if lop == AND:
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to_write += '{}\n'.format(cx.to_pyrat())
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to_write += '{}\n'.format(cy.to_pyrat())
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else:
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print('Error, PyRAT output format does not support \
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OR operator. Aborting conversion.')
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raise ValueError
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return to_write
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def write_smtlib(self, fpath='formula.smt2'):
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with open(fpath, 'w') as f:
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to_write = self.to_smtlib()
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to_write += '(check-sat)\n'
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to_write += '(get-value (|CELL_actual_input_0_0_0|))\n'
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to_write += '(get-value (|CELL_actual_input_0_0_1|))\n'
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to_write += '(get-value (|CELL_actual_input_0_0_2|))\n'
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to_write += '(get-value (|CELL_actual_output_0_0_0|))\n'
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f.write(to_write)
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print('Wrote SMT formula in file {}'.format(fpath))
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def write_marabou(self, fpath='formula.marabou'):
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with open(fpath, 'w') as f:
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to_write = self.to_marabou()
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f.write(to_write)
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print('Wrote marabou formula in file {}'.format(fpath))
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def write_pyrat(self, fpath='formula.txt'):
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with open(fpath, 'w') as f:
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to_write = self.to_pyrat()
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f.write(to_write)
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print('Wrote pyrat formula in file {}'.format(fpath))
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def formula_p1():
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distance = Var('x0')
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angle1 = Var('x1')
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angle2 = Var('x2')
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speed1 = Var('x3')
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speed2 = Var('x4')
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output = Var('y0')
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constrs = []
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constrs.append(Constr(distance, '>=', Real(0.6)))
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constrs.append(Constr(distance, '<', Real(0.6798577687)))
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constrs.append(Constr(angle1, '>=', Real(-0.5)))
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constrs.append(Constr(angle1, '<', Real(0.5)))
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constrs.append(Constr(angle2, '>=', Real(-0.5)))
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constrs.append(Constr(angle2, '<', Real(0.5)))
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constrs.append(Constr(speed1, '>=', Real(0.45)))
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constrs.append(Constr(speed1, '<', Real(0.5)))
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constrs.append(Constr(speed2, '>=', Real(-0.5)))
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constrs.append(Constr(speed2, '<', Real(-0.45)))
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constrs.append(Constr(output, '<', Real(3.9911256459)))
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formula = Formula()
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for c in constrs:
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formula.add(c)
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return formula
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