+
+ def to_isl(self):
+ #d = Expression().__dict__ #write expression values to dictionary in form {'_constant': value, '_coefficients': value}
+ d = {'_constant': 2, '_coefficients': {'b':1}}
+ coeff = d.get('_coefficients')
+ num_coefficients = len(coeff)
+ space = libisl.isl_space_set_alloc(Context(), 0, num_coefficients)
+ bset = libisl.isl_basic_set_empty(libisl.isl_space_copy(space))
+ ls = libisl.isl_local_space_from_space(libisl.isl_space_copy(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
+ need to change the symbols method to a lookup table for the integer value for each letter that could be a symbol'''
+ if self._equalities:
+ if '_constant' in d:
+ value = d.get('_constant')
+ ceq = libisl.isl_constraint_set_constant_si(ceq, value)
+ if '_coefficients' in d:
+ value_co = d.get('_coefficients')
+ for co in value_co:
+ num = value_co.get(co)
+ ceq = libisl.isl_constraint_set_coefficient_si(ceq, 3, get_ids(co), num) #use 3 for type isl_dim_set
+ bset = libisl.isl_set_add_constraint(bset, ceq)
+
+ if self._inequalities:
+ if '_constant' in d:
+ value = d.get('_constant')
+ cin = libisl.isl_constraint_set_constant_si(cin, value)
+ if '_coefficients' in d:
+ value_co = d.get('_coefficients')
+ for co in value_co:
+ num = value_co.get(co)
+ if value_co: #if dictionary not empty add coefficient as to constraint
+ cin = libisl.isl_constraint_set_coefficient_si(cin, 3, get_ids(co), num) #use 3 for type isl_dim_set
+ bset = libisl.isl_set_add_constraint(bset, cin)
+ ip = libisl.isl_printer_to_str(Context()) #create string printer
+ ip = libisl.isl_printer_print_set(ip, bset) #print set to printer
+ string = libisl.isl_printer_get_str(ip) #get string from printer
+ string = str(string)
+ print(string)
+ return string
+
+
+ def from_isl(self, bset):
+ '''takes basic set in isl form and puts back into python version of polyhedron
+ isl example code gives idl form as:
+ "{[i] : exists (a : i = 2a and i >= 10 and i <= 42)}");'''
+
+ poly = 0
+ return poly
+
+empty = eq(1,1)