Don't fuse elemwise where the scalar don't have a c_code implemented.

theano/tensor/opt.py

@@ -6,6 +6,7 @@
 
 from theano import gof
 from theano.gof import opt, InconsistencyError, TopoOptimizer, graph
+from theano.gof.utils import MethodNotDefined
 from elemwise import Elemwise, DimShuffle
 from theano import scalar
 import basic as T
@@ -1246,7 +1247,23 @@ def local_elemwise_fusion(node):
     s_inputs = []#inputs of the new scalar op.
     s_g=[]#graph of scalar, what will by done in the inner loop.
     for i in node.inputs:
+        do_fusion = False
+        catch = False
         if i.owner and isinstance(i.owner.op,T.Elemwise) and len(i.clients)<=1:
+            #if the scalar_op don't have a c implementation, we skip its fusion to allow the fusion of the other ops.
+            do_fusion=True
+            try:
+                i.owner.op.scalar_op.c_code(i,"test_presence_of_c_code",
+                                            i.owner.inputs,i.owner.outputs,{})
+            except MethodNotDefined:
+                catch = True
+            except NotImplementedError:
+                catch = True
+            if catch:
+                print "OPTIMISATION WARNING: ",i.owner.op.scalar_op,"don't implement the c_code fonction. This is not fast and disable the fusion of loop."
+                do_fusion=False
+
+        if do_fusion:
             if len(i.clients)>1:
                 #should we put this in the first if, then we would go to the elif to don't fuse it?
     #if one of the inputs have more then 1 clients and it is an intermediate result. We don't fuse.        

theano/tensor/tests/test_opt.py

@@ -874,7 +874,7 @@ class test_fusion(unittest.TestCase):
             (fx+fy+theano.tensor.exp(fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv+fyv+numpy.exp(fzv),'float32'),#35
             (fx-fy-fz,(fx,fy,fz),(fxv,fyv,fzv),1,fxv-fyv-fzv,'float32'),
             (fx-(fy/fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv/fzv),'float32'),
-#            (fx-(fy%fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv%fzv),'float32'),#TODO: c_code not implemented for %
+            (fx-(fy%fz),(fx,fy,fz),(fxv,fyv,fzv),2,fxv-(fyv%fzv),'float32'),#TODO: c_code not implemented for %
             (fx-(fy>fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv>fzv),'float32'),
             (fx-(fy>=fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv>=fzv),'float32'),
             (fx-(fy<fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv<fzv),'float32'),