#!/usr/bin/env python3
+# This is an implementation of the algorithm described in
+#
+# [ACI10] C. Ancourt, F. Coelho and F. Irigoin, A modular static analysis
+# approach to affine loop invariants detection (2010), pp. 3 - 16, NSAD 2010.
+#
+# to compute the transitive closure of an affine transformer. A refined version
+# of this algorithm is implemented in PIPS.
+
from linpy import *
if __name__ == '__main__':
- i, iprime, j, jprime = symbols("i i' j j'")
- transformer = Transformer(Eq(iprime, i + 2) & Eq(jprime, j + 1),
- [i, j], [iprime, jprime])
+ i0, i, j0, j = symbols('i0 i j0 j')
+ transformer = Transformer(Eq(i, i0 + 2) & Eq(j, j0 + 1),
+ [i0, j0], [i, j])
print('T =', transformer.polyhedron)
print('T* =', transformer.star().polyhedron)