dependencies check and also speed up

theano/gof/vm.py

@@ -150,7 +150,11 @@ class VM(object):
             profile.node_cleared_order = self.node_cleared_order[:]
 
         if hasattr(self, 'dependencies'):
+            if self.dependencies:
                 profile.dependencies = self.dependencies.copy()
+            else:
+                profile.dependencies = {}
+
 
         # clear the timer info out of the buffers
         for i in xrange(len(self.call_times)):
@@ -897,6 +901,7 @@ class VM_Linker(link.LocalLinker):
             for var in fgraph.variables:
                 viewed_by[var] = []
             view_of = {}
+            reallocated_info = {}
 
             for idx in range(len(order)):
                 node = order[idx]
@@ -925,13 +930,16 @@ class VM_Linker(link.LocalLinker):
 
                 for ins in node.inputs:
                     assert not (ins in view_of and viewed_by[ins])
-                    if (ins.ndim == 0 and storage_map[ins][0] and ins not in fgraph.outputs and ins.owner):
+                    if (ins.ndim == 0 and not storage_map[ins][0] and ins not in fgraph.outputs and ins.owner):
+                        # Constant Memory cannot be changed, Constant storage_map has a value here
                         reuse_outs = []
                         if ins not in view_of and not viewed_by.get(ins, []):
                             # where gc
                             for i in range(idx + 1, len(order)):
+                                if reuse_outs:
+                                    break
                                 for outs in order[i].outputs:
-                                    if outs.ndim == 0 and out not in viewed_by.values():
+                                    if outs.ndim == 0 and outs not in viewed_by.get(ins, []):
                                         reuse_outs.append(outs)
                         elif ins in view_of:
                             origin = view_of[ins]
@@ -941,13 +949,16 @@ class VM_Linker(link.LocalLinker):
                                     not isinstance(origin, theano.Constant)):
                                 #where gc
                                 for i in range(idx + 1, len(order)):
+                                    if reuse_outs:
+                                        break
                                     for outs in order[i].outputs:
-                                        if outs.ndim == 0 and out not in viewed_by.values():
+                                        if outs.ndim == 0 and outs not in viewed_by.get(ins, []):
                                             reuse_outs.append(outs)
 
                         if reuse_outs:
                             # if reusable output variable exists
                             reallocated_ins.add(ins)
+                            reallocated_info[ins] = reuse_outs
 
         for node in order:
             try: