From 4ae512f39c14835badbfab6fc1ce877f601d104e Mon Sep 17 00:00:00 2001
From: Vivien Maisonneuve <v.maisonneuve@gmail.com>
Date: Tue, 1 Jul 2014 18:47:54 +0200
Subject: [PATCH] Alternative implementation of projection
---
pypol/domains.py | 26 +++++++++++---------------
pypol/tests/test_domains.py | 10 +++++-----
2 files changed, 16 insertions(+), 20 deletions(-)
diff --git a/pypol/domains.py b/pypol/domains.py
index be87ffb..c844e55 100644
--- a/pypol/domains.py
+++ b/pypol/domains.py
@@ -139,7 +139,7 @@ class Domain:
def simplify(self):
#does not change anything in any of the examples
- #isl seems to do this naturally
+ #isl seems to do this naturally
islset = self._toislset(self.polyhedra, self.symbols)
islset = libisl.isl_set_remove_redundancies(islset)
return self._fromislset(islset, self.symbols)
@@ -152,21 +152,17 @@ class Domain:
islbset = libisl.isl_set_polyhedral_hull(islset)
return Polyhedron._fromislbasicset(islbset, self.symbols)
- def drop_dims(self, dims):
- # use to remove certain variables use isl_set_drop_constraints_involving_dims instead?
- from .polyhedra import Polyhedron
- dims = list(dims)
- symbols = list(self.symbols)
+ def project_out(self, symbols):
+ # use to remove certain variables
islset = self._toislset(self.polyhedra, self.symbols)
- for dim in dims:
- if dim in symbols:
- first = symbols.index(dim)
- islbset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, first, 1)
- symbols.__delitem__(first)
- else:
- islbset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, 0, 0)
- return Polyhedron._fromislset(islbset, symbols)
-
+ # the trick is to walk symbols in reverse order, to avoid index updates
+ for index, symbol in reversed(list(enumerate(self.symbols))):
+ if symbol in symbols:
+ islset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, index, 1)
+ # remaining symbols
+ symbols = [symbol for symbol in self.symbols if symbol not in symbols]
+ return Domain._fromislset(islset, symbols)
+
def sample(self):
from .polyhedra import Polyhedron
islset = self._toislset(self.polyhedra, self.symbols)
diff --git a/pypol/tests/test_domains.py b/pypol/tests/test_domains.py
index 692627c..55853fd 100644
--- a/pypol/tests/test_domains.py
+++ b/pypol/tests/test_domains.py
@@ -77,11 +77,11 @@ class TestDomain(unittest.TestCase):
def test_polyhedral_hull(self):
self.assertEqual(self.square1.polyhedral_hull(), self.hull)
- def test_drop_dims(self):
- self.assertEqual(self.square1.drop_dims('x'), self.dropped)
- self.assertEqual(self.square1.drop_dims('x y'), self.universe)
- self.assertEqual(self.universe.drop_dims(' '), self.universe)
- self.assertEqual(self.empty.drop_dims(' '), Empty)
+ def test_project_out(self):
+ self.assertEqual(self.square1.project_out('x'), self.dropped)
+ self.assertEqual(self.square1.project_out('x y'), self.universe)
+ self.assertEqual(self.universe.project_out(' '), self.universe)
+ self.assertEqual(self.empty.project_out(' '), Empty)
def test_simplify(self):
self.assertEqual(self.universe.simplify(), self.universe)
--
2.20.1