From 8fe086b5ae03df5fadf1ec7de1aa41c0ace4a3ae Mon Sep 17 00:00:00 2001
From: Danielle Bolan <n02702451@hawkmail.newpaltz.edu>
Date: Wed, 2 Jul 2014 11:10:14 +0200
Subject: [PATCH 1/1] Add to drop_dims check next value, a little sloppy

---
 pypol/domains.py | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/pypol/domains.py b/pypol/domains.py
index 6060dc9..bbb0946 100644
--- a/pypol/domains.py
+++ b/pypol/domains.py
@@ -5,7 +5,7 @@ import re
 from . import islhelper
 
 from .islhelper import mainctx, libisl, isl_set_basic_sets
-from .linexprs import Expression, Symbol, symbolnames
+from .linexprs import Expression
 
 
 __all__ = [
@@ -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)
@@ -152,18 +152,29 @@ class Domain:
         islbset = libisl.isl_set_polyhedral_hull(islset)
         return Polyhedron._fromislbasicset(islbset, self.symbols)
 
-    def project_out(self, symbols):
-        # use to remove certain variables
-        symbols = symbolnames(symbols)
+    def drop_dims(self, dims):
+        # use to remove certain variables use isl_set_drop_constraints_involving_dims instead?
+        from .polyhedra import Polyhedron 
+        n = 1     
+        dims = list(dims)
+        symbols = list(self.symbols)
         islset = self._toislset(self.polyhedra, self.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)
-
+        for dim in dims:
+            dim_index = dims.index(dim)
+            if dim in symbols:
+                first = symbols.index(dim) 
+                try:
+                    if symbols[first+1] is dims[dim_index+1]: #check if next value in symbols is same as next value in dims
+                        n += 1
+                        islbset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, first, n)  
+                        symbols.__delitem__(first)
+                except:
+                    islbset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, first, n)  
+                symbols.__delitem__(first)     
+            else:
+                islbset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, 0, 0)        
+        return Polyhedron._fromislset(islbset, symbols)
+    
     def sample(self):
         from .polyhedra import Polyhedron
         islset = self._toislset(self.polyhedra, self.symbols)
@@ -241,7 +252,6 @@ class Domain:
             self._dimension = len(self._symbols)
             return self
 
-    @classmethod
     def _toislset(cls, polyhedra, symbols):
         polyhedron = polyhedra[0]
         islbset = polyhedron._toislbasicset(polyhedron.equalities,
@@ -338,7 +348,6 @@ class Domain:
     def tosympy(self):
         raise NotImplementedError
 
-
 def And(*domains):
     if len(domains) == 0:
         from .polyhedra import Universe
-- 
2.20.1