+ def _symbolunion(self, *others):
+ symbols = set(self.symbols())
+ for other in others:
+ symbols.update(other.symbols())
+ return sorted(symbols)
+
+ def _to_isl(self, symbols=None):
+ if symbols is None:
+ symbols = self.symbols()
+ num_coefficients = len(symbols)
+ ctx = Context()
+ space = libisl.isl_space_set_alloc(ctx, 0, num_coefficients)
+ bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))
+ ls = libisl.isl_local_space_from_space(space)
+ ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
+ cin = libisl.isl_inequality_alloc(libisl.isl_local_space_copy(ls))
+ '''if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set'''
+ if list(self.equalities): #check if any equalities exist
+ for eq in self.equalities:
+ coeff_eq = dict(eq.coefficients)
+ if eq.constant:
+ value = eq.constant
+ ceq = libisl.isl_constraint_set_constant_si(ceq, value)
+ for eq in coeff_eq:
+ num = coeff_eq.get(eq)
+ iden = symbols.index(eq)
+ ceq = libisl.isl_constraint_set_coefficient_si(ceq, islhelper.isl_dim_set, iden, num) #use 3 for type isl_dim_set
+ bset = libisl.isl_basic_set_add_constraint(bset, ceq)
+ if list(self.inequalities): #check if any inequalities exist
+ for ineq in self.inequalities:
+ coeff_in = dict(ineq.coefficients)
+ if ineq.constant:
+ value = ineq.constant
+ cin = libisl.isl_constraint_set_constant_si(cin, value)
+ for ineq in coeff_in:
+ num = coeff_in.get(ineq)
+ iden = symbols.index(ineq)
+ cin = libisl.isl_constraint_set_coefficient_si(cin, islhelper.isl_dim_set, iden, num) #use 3 for type isl_dim_set
+ bset = libisl.isl_basic_set_add_constraint(bset, cin)
+ ip = libisl.isl_printer_to_str(ctx) #create string printer
+ ip = libisl.isl_printer_print_basic_set(ip, bset) #print basic set to printer
+ string = libisl.isl_printer_get_str(ip) #get string from printer
+ string = str(string.decode())
+ print(string)
+ return bset
+
+ def from_isl(self, bset):
+ '''takes basic set in isl form and puts back into python version of polyhedron
+ isl example code gives isl form as:
+ "{[i] : exists (a : i = 2a and i >= 10 and i <= 42)}")
+ our printer is giving form as:
+ b'{ [i0] : 1 = 0 }' '''
+ #bset = self
+ if self._equalities:
+ constraints = libisl.isl_basic_set_equalities_matrix(bset, 3)
+ elif self._inequalities:
+ constraints = libisl.isl_basic_set_inequalities_matrix(bset, 3)
+ print(constraints)
+ return constraints
+
+empty = None #eq(0,1)
+universe = None #Polyhedron()
+
+if __name__ == '__main__':
+ ex1 = Expression(coefficients={'a': 1, 'x': 2}, constant=2)
+ ex2 = Expression(coefficients={'a': 3 , 'b': 2}, constant=3)
+ p = Polyhedron(inequalities=[ex1, ex2])
+ #p = eq(ex2, 0)# 2a+4 = 0, in fact 6a+3 = 0
+ #p.to_isl()
+
+#universe = Polyhedron()