Update drop_dims, now works with more than 2 dims passed

[linpy.git] / pypol / domains.py

diff --git a/pypol/domains.py b/pypol/domains.py
index 6b47fe8..3bcfa24 100644 (file)
--- 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
+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)
@@ -152,26 +152,30 @@ 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
-        if isinstance(symbols, str):
-            symbols = symbols.replace(',', ' ').split()
-        else:
-            symbols = list(symbols)
-            for i, symbol in enumerate(symbols):
-                if isinstance(symbol, Symbol):
-                    symbols[i] = symbol.name
-                elif not isinstance(symbol, str):
-                    raise TypeError('symbols must be strings or Symbol instances')
+    def drop_dims(self, dims):
+        # use to remove certain variables use isl_set_drop_constraints_involving_dims instead?
+        from .polyhedra import Polyhedron 
+        n = 0 
+        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:
+                    for dim in dims:
+                        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.remove(dim)
+                except:
+                    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)
+    
     def sample(self):
         from .polyhedra import Polyhedron
         islset = self._toislset(self.polyhedra, self.symbols)