put the fusion of elemwise after the gemm optimizer as this make the gemm…

theano/tensor/blas.py

@@ -597,6 +597,7 @@ class GemmOptimizer(Optimizer):
                         #TODO: retry other applications of gemm (see comment in _gemm_from_node
                         pass
 
+#neede to make the gemm optimisation(step 70) happen before the fusion of elemwise(step 71)
 compile.optdb.register('inplace_gemm', GemmOptimizer(), 70.00, 'fast_run', 'inplace', 'gemm')
 
 

theano/tensor/opt.py

@@ -20,7 +20,8 @@ import sys, os
 from theano import compile  #to register the optimizer built by this file
 
 from theano.gof.python25 import any, all
-
+from theano.gof.opt import Optimizer
+from theano.gof import toolbox, DestroyHandler
 # Utilities
 
 def out2in(*local_opts):
@@ -1231,7 +1232,6 @@ register_canonicalize(local_transposed_dot, name='local_transposed_dot')
 # # Loop fusion #
 # ###############
 
-@gof.local_optimizer([T.Elemwise, T.Elemwise])
 def local_elemwise_fusion(node):
     """
     As part of specialisation, we fusion two consecutif elemwise op of the same shape.
@@ -1339,9 +1339,38 @@ def local_elemwise_fusion(node):
 #    print "local_elemwise_fusion: FUSED",nb_elemwise+1,"elemwise!"
     return n.outputs
 
+class FusionOptimizer(Optimizer):
+    """Graph optimizer for Fusion of elemwise operations"""
+    def __init__(self):
+        Optimizer.__init__(self)
+
+    def add_requirements(self, env):
+        env.extend(toolbox.ReplaceValidate())
+        env.extend(DestroyHandler())
+
+    def apply(self, env):
+        did_something = True
+        while did_something:
+            nodelist = list(env.toposort())
+            did_something = False
+            for node in nodelist:
+                new_outputs = local_elemwise_fusion(node)
+                if new_outputs:
+                    assert len(new_outputs) == len(node.outputs)
+                    try:
+                        env.replace_all_validate(
+                                zip(node.outputs, new_outputs),
+                                reason = self.__class__.__name__)
+                        did_something = True
+                        break
+                    except InconsistencyError, e:
+                        #TODO: retry other applications of gemm (see comment in _gemm_from_node
+                        pass
+
+
 if config.getboolean('tensor_opt.local_elemwise_fusion'):
     _logger.debug("enabling optimization: fusion elemwise")
-    register_specialize(local_elemwise_fusion)
+    compile.optdb.register('elemwise_fusion', FusionOptimizer(), 71.00, 'fast_run', 'fusion')
 else:
     _logger.debug("not enabling optimization: fusion elemwise")