implemented the c_code for the scalar mod op. It correctly implement the python…

theano/scalar/basic.py

@@ -752,7 +752,30 @@ class Mod(BinaryScalarOp):
     def impl(self, x, y):
         return x % y
     def c_code(self, node, name, (x, y), (z, ), sub):
-        raise NotImplementedError("Unlike Python, C's modulo returns negative modulo on negative dividend (to implement)")
+        """
+        We want the result to have the same sign as python, not the other implementaiton of mod.
+        """
+        #raise NotImplementedError("Unlike Python, C's modulo returns negative modulo on negative dividend (to implement)")
+        return """
+    if (%(x)s == 0 || %(y)s == 0) {
+        if (%(y)s == 0) %(z)s = %(x)s %% %(y)s;
+        %(z)s = 0;
+    }
+//was #if @neg@, I suspect @neg@ to be platform dependant.
+//should be true under X86, but could be false for other architecture!
+#if 1
+    else if ((%(x)s > 0) == (%(y)s > 0)) {
+        %(z)s = %(x)s %% %(y)s;
+    }
+    else { /* handled like Python does */
+        %(z)s = %(x)s %% %(y)s;
+        if (%(z)s) %(z)s += %(y)s;
+    }
+#else
+    else
+        %(z)s = %(x)s %% %(y)s;
+#endif
+"""%locals()
     def grad(self, (x, y), (gz, )):
         return None, None
 mod = Mod(upcast_out, name = 'mod')

theano/scalar/tests/test_basic.py

@@ -31,6 +31,19 @@ class test_ScalarOps(unittest.TestCase):
         fn = gof.DualLinker().accept(g).make_function()
         assert fn(1.0, 2.0) == 1.5
 
+    def test_mod(self):
+        """
+        We add this test as not all language and C implementation give the same 
+        signe to the result. This check that the c_code of `Mod` is implemented
+        as Python. That is what we want.
+        """
+        x, y = ints('xy')
+        fn = gof.DualLinker().accept(Env([x,y], [x%y])).make_function()
+        for a,b in ((0,1), (1,1), (0,-1), (1,-1), (-1,-1),
+                    (1,2), (-1,2), (1,-2), (-1,-2),
+                    (5,3), (-5,3), (5,-3), (-5,-3)
+                    ):
+            self.failUnless(fn(a,b) == a%b, (a,))
 
 class test_composite(unittest.TestCase):
 

theano/tensor/tests/test_opt.py

@@ -874,12 +874,12 @@ 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),2,fxv-(fyv%fzv),'float32'),#TODO: c_code not implemented for %
+            (fx-(fy%fz),(fx,fy,fz),(fxv,fyv,fzv),2,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'),
+            (fx-(fy>=fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv>=fzv),'float32'),#40
             (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: bugged
+            (fx-(fy<=fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv<=fzv),'float32'),#TODO: bugged on the gpu
+            (fx-(fy==fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv==fzv),'float32'),#TODO: bugged
             (fx-(fy!=fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-(fyv!=fzv),'float32'),
             (fx-fy+tan(fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-fyv+numpy.tan(fzv),'float32'),
             (fx-fy+tanh(fz),(fx,fy,fz),(fxv,fyv,fzv),1,fxv-fyv+numpy.tanh(fzv),'float32'),