Fix a bug found with James in CudaNdarray.__getitem__ with negitave index.

theano/sandbox/cuda/cuda_ndarray.cu

@@ -1098,12 +1098,12 @@ CudaNdarray_Subscript(PyObject * py_self, PyObject * key)
         else if ((d_idx < 0) && (d_idx >= -d_dim))
         {
             //end-based indexing
-            offset += (d_dim - d_idx) * CudaNdarray_HOST_STRIDES(self)[0];
+            // d_idx is negative
+            offset += (d_dim + d_idx) * CudaNdarray_HOST_STRIDES(self)[0];
         }
         else
         {
             PyErr_SetString(PyExc_IndexError, "index out of bounds");
-            Py_DECREF(rval);
             return NULL;
         }
 

theano/sandbox/cuda/tests/test_cuda_ndarray.py

@@ -257,32 +257,54 @@ def test_mapping_getitem_w_int():
             print y
         assert numpy.all(x == y)
 
+    def _cmpf(x,*y):
+        try:
+            x.__getitem__(y)
+	except IndexError:
+            pass
+	else:
+            raise Exception("Did not generate out or bound error")
+
     dim =(2,)
     a = theano._asarray(numpy.random.rand(*dim), dtype='float32')
     _a = cuda_ndarray.CudaNdarray(a)
     _cmp(numpy.asarray(_a[1]), a[1])
+    _cmp(numpy.asarray(_a[-1]), a[-1])
+    _cmp(numpy.asarray(_a[0]), a[0])
     _cmp(numpy.asarray(_a[::1]), a[::1])
     _cmp(numpy.asarray(_a[::-1]), a[::-1])
     _cmp(numpy.asarray(_a[...]), a[...])
+    _cmpf(_a,2)
 
     dim =()
     a = theano._asarray(numpy.random.rand(*dim), dtype='float32')
     _a = cuda_ndarray.CudaNdarray(a)
     _cmp(numpy.asarray(_a[...]), a[...])
-
+    #TODO: test slice err
+    #TODO: test tuple err
 
 
     dim =(5,4,3,2)
     a = theano._asarray(numpy.random.rand(*dim), dtype='float32')
     _a = cuda_ndarray.CudaNdarray(a)
 
+    _cmpf(_a,slice(-1),slice(-1),10,-10)
+    _cmpf(_a,slice(-1),slice(-1),-10,slice(-1))
+    _cmpf(_a,0,slice(0,-1,-20),-10)
+    _cmpf(_a,10)
+    _cmpf(_a,-10)
+
     _cmp(numpy.asarray(_a[:,:,::-1, ::-1]), a[:,:,::-1,::-1])
+    _cmp(numpy.asarray(_a[:,:,::-10, ::-10]), a[:,:,::-10,::-10])
     _cmp(numpy.asarray(_a[:,:,1,-1]), a[:,:,1,-1])
     _cmp(numpy.asarray(_a[:,:,-1,:]), a[:,:,-1,:])
     _cmp(numpy.asarray(_a[:,::-2,-1,:]), a[:,::-2,-1,:])
+    _cmp(numpy.asarray(_a[:,::-20,-1,:]), a[:,::-20,-1,:])
     _cmp(numpy.asarray(_a[:,::-2,-1]), a[:,::-2,-1])
     _cmp(numpy.asarray(_a[0,::-2,-1]), a[0,::-2,-1])
     _cmp(numpy.asarray(_a[1]), a[1])
+    _cmp(numpy.asarray(_a[-1]), a[-1])
+    _cmp(numpy.asarray(_a[-1,-1,-1,-2]), a[-1,-1,-1,-2])
     _cmp(numpy.asarray(_a[...]), a[...])
 
 def test_gemm_vector_vector():