index 4b73eef..3de2ebd 100755 (executable)
@@ -8,7 +8,7 @@
# to compute the transitive closure of an affine transformer. A refined version
# of this algorithm is implemented in PIPS.

-from linpy import *
+from linpy import Dummy, Eq, Ge, Polyhedron, symbols

class Transformer:
@@ -28,7 +28,8 @@ class Transformer:
delta_symbols = [symbol.asdummy() for symbol in self.range_symbols]
k = Dummy('k')
polyhedron = self.polyhedron
-        for x, xprime, dx in zip(self.range_symbols, self.domain_symbols, delta_symbols):
+        for x, xprime, dx in zip(
+                self.range_symbols, self.domain_symbols, delta_symbols):
polyhedron &= Eq(dx, xprime - x)
polyhedron = polyhedron.project(self.symbols)
equalities, inequalities = [], []
@@ -40,7 +41,8 @@ class Transformer:
inequalities.append(inequality)
polyhedron = Polyhedron(equalities, inequalities) & Ge(k, 0)
polyhedron = polyhedron.project([k])
-        for x, xprime, dx in zip(self.range_symbols, self.domain_symbols, delta_symbols):
+        for x, xprime, dx in zip(
+                self.range_symbols, self.domain_symbols, delta_symbols):
polyhedron &= Eq(dx, xprime - x)
polyhedron = polyhedron.project(delta_symbols)
return Transformer(polyhedron, self.range_symbols, self.domain_symbols)
@@ -49,6 +51,6 @@ class Transformer:
if __name__ == '__main__':
i0, i, j0, j = symbols('i0 i j0 j')
transformer = Transformer(Eq(i, i0 + 2) & Eq(j, j0 + 1),
-        [i0, j0], [i, j])
+                              [i0, j0], [i, j])
print('T  =', transformer.polyhedron)
print('T* =', transformer.star().polyhedron)