fix trimming

nutils/topology.py

@@ -371,13 +371,14 @@ def _trim(self, levelset, maxrefine, ndivisions=8, leveltopo=None, *, arguments=
       arguments = {}
 
     refs = []
+    levelset = levelset.prepare_eval(subsamples=(function.SubsampleMeta(roots=self.roots, ndimsnormal=sum(root.ndims for root in self.roots)-self.ndims),), transforms=(self.transforms, self.opposites)).simplified
     if leveltopo is None:
-      verts = self.sample('vertex', maxrefine)
-      levels = verts.eval(levelset)
-      refs = [ref.trim(levels[verts.getindex(ielem)], maxrefine=maxrefine, ndivisions=ndivisions) for ielem, ref in enumerate(self.references)]
+      with log.iter.percentage('trimming', self.references, self.transforms, self.opposites) as items:
+        for ielem, (ref, trans, opp) in enumerate(items):
+          levels = levelset.eval(function.Subsample(roots=self.roots, transforms=(self.transforms, self.opposites), points=ref.getpoints('vertex', maxrefine), ielem=ielem), **arguments)
+          refs.append(ref.trim(levels, maxrefine=maxrefine, ndivisions=ndivisions))
     else:
       log.info('collecting leveltopo elements')
-      levelset = levelset.prepare_eval(subsamples=(function.SubsampleMeta(roots=self.roots, ndimsnormal=sum(root.ndims for root in self.roots)-self.ndims),), transforms=(self.transforms, self.opposites)).simplified
       bins = [dict() for ielem in range(len(self))]
       for ielemlevel, trans in enumerate(leveltopo.transforms):
         ielem, tail = self.transforms.index_with_tail(trans)