Coding style in _toisl()

diff --git a/pypol/linear.py b/pypol/linear.py
index 621a157..3939c71 100644 (file)
--- a/pypol/linear.py
+++ b/pypol/linear.py
@@ -524,7 +524,6 @@ class Polyhedron:
         difference = libisl.isl_set_subtract(bset, other)
         return difference
 
-
     def __sub__(self, other):
         return self.difference(other)
 
@@ -556,36 +555,33 @@ class Polyhedron:
     def _toisl(self, symbols=None):
         if symbols is None:
             symbols = self.symbols
-        num_coefficients = len(symbols)
-        space = libisl.isl_space_set_alloc(_main_ctx, 0, num_coefficients)
+        dimension = len(symbols)
+        space = libisl.isl_space_set_alloc(_main_ctx, 0, dimension)
         bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))
         ls = libisl.isl_local_space_from_space(space)
-        #if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set
-        for eq in self.equalities:
+        for equality in self.equalities:
             ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
-            coeff_eq = dict(eq.coefficients())
-            if eq.constant:
-                value = str(eq.constant).encode()
-                val = libisl.isl_val_read_from_str(_main_ctx, value)
+            for symbol, coefficient in equality.coefficients():
+                val = str(coefficient).encode()
+                val = libisl.isl_val_read_from_str(_main_ctx, val)
+                dim = symbols.index(symbol)
+                ceq = libisl.isl_constraint_set_coefficient_val(ceq, libisl.isl_dim_set, dim, val)
+            if equality.constant != 0:
+                val = str(equality.constant).encode()
+                val = libisl.isl_val_read_from_str(_main_ctx, val)
                 ceq = libisl.isl_constraint_set_constant_val(ceq, val)
-            for eq in coeff_eq:
-                number = str(coeff_eq.get(eq)).encode()
-                num = libisl.isl_val_read_from_str(_main_ctx, number)
-                iden = symbols.index(eq)
-                ceq = libisl.isl_constraint_set_coefficient_val(ceq, libisl.isl_dim_set, iden, num)  #use 3 for type isl_dim_set
             bset = libisl.isl_basic_set_add_constraint(bset, ceq)
-        for ineq in self.inequalities:
+        for inequality in self.inequalities:
             cin = libisl.isl_inequality_alloc(libisl.isl_local_space_copy(ls))
-            coeff_in = dict(ineq.coefficients())
-            if ineq.constant:
-                value = str(ineq.constant).encode()
-                val = libisl.isl_val_read_from_str(_main_ctx, value)
+            for symbol, coefficient in inequality.coefficients():
+                val = str(coefficient).encode()
+                val = libisl.isl_val_read_from_str(_main_ctx, val)
+                dim = symbols.index(symbol)
+                cin = libisl.isl_constraint_set_coefficient_val(cin, libisl.isl_dim_set, dim, val)
+            if inequality.constant != 0:
+                val = str(ineq.constant).encode()
+                val = libisl.isl_val_read_from_str(_main_ctx, val)
                 cin = libisl.isl_constraint_set_constant_val(cin, val)
-            for ineq in coeff_in:
-                number = str(coeff_in.get(ineq)).encode()
-                num = libisl.isl_val_read_from_str(_main_ctx, number)
-                iden = symbols.index(ineq)
-                cin = libisl.isl_constraint_set_coefficient_val(cin, libisl.isl_dim_set, iden, num)  #use 3 for type isl_dim_set
             bset = libisl.isl_basic_set_add_constraint(bset, cin)
         bset = isl.BasicSet(bset)
         return bset
@@ -606,8 +602,9 @@ Empty = eq(0,1)
 Universe = Polyhedron()
 
 if __name__ == '__main__':
-    ex1 = Expression(coefficients={'a': 6, 'b': 6}, constant= 3) #this is the expression that does not work (even without adding values)
-    ex2 = Expression(coefficients={'x': 4, 'y': 2}, constant= 3)
-    p = Polyhedron(equalities=[ex2])
-    p2 = Polyhedron(equalities=[ex2])
-    print(p._toisl()) # checking is values works for toisl
+    e1 = Expression(coefficients={'a': 2, 'b': 2}, constant= 1)
+    p1 = Polyhedron(equalities=[e1]) # empty
+    e2 = Expression(coefficients={'x': 3, 'y': 2}, constant= 3)
+    p2 = Polyhedron(equalities=[e2]) # not empty
+    print(p1._toisl())
+    print(p2._toisl())