Add construction function for LoDTensor in pybind.

paddle/pybind/pybind.cc

@@ -125,10 +125,23 @@ The tensor and LoD info should be created before creating the LoDTensor, then
 call the set_tensor and set_lod functions to set them.
 
 )DOC")
+      .def("__init__",
+           [](LoDTensor &instance,
+              const std::vector<std::vector<size_t>> &lod,
+              Tensor *t) {
+#ifdef PADDLE_ONLY_CPU
+             new (&instance) LoDTensor(lod, t);
+#else
+             paddle::framework::LoD new_lod;
+             new_lod.reserve(lod.size());
+             std::copy(lod.begin(), lod.end(), std::back_inserter(new_lod));
+             new (&instance) LoDTensor(new_lod, t);
+#endif
+           })
       .def("set_tensor",
            [](LoDTensor &self, Tensor *tensor) { self.set_tensor(tensor); })
       .def("set_lod",
-           [](LoDTensor &self, std::vector<std::vector<size_t>> &lod) {
+           [](LoDTensor &self, const std::vector<std::vector<size_t>> &lod) {
 #ifdef PADDLE_ONLY_CPU
              self.set_lod(lod);
 #else

python/paddle/v2/framework/tests/test_tensor.py

@@ -44,10 +44,11 @@ class TestTensor(unittest.TestCase):
         self.assertAlmostEqual(2.0, tensor_array_2[19, 11])
 
     def test_int_lod_tensor(self):
+        places = [core.CPUPlace(), core.GPUPlace(0)]
+        for place in places:
             scope = core.Scope()
             var = scope.new_var("test_tensor")
             var_lod = scope.new_var("test_lod_tensor")
-        place = core.CPUPlace()
 
             tensor = var.get_tensor()
             lod_tensor = var_lod.get_lod_tensor()
@@ -71,10 +72,11 @@ class TestTensor(unittest.TestCase):
             self.assertEqual(4, lod[0][2])
 
     def test_float_lod_tensor(self):
+        places = [core.CPUPlace(), core.GPUPlace(0)]
+        for place in places:
             scope = core.Scope()
             var = scope.new_var("test_tensor")
             var_lod = scope.new_var("test_lod_tensor")
-        place = core.CPUPlace()
 
             tensor = var.get_tensor()
             lod_tensor = var_lod.get_lod_tensor()
@@ -100,6 +102,25 @@ class TestTensor(unittest.TestCase):
             lod = lod_tensor.lod()
             self.assertListEqual(lod_py, lod)
 
+    def test_lod_tensor_init(self):
+        scope = core.Scope()
+        var = scope.new_var("test_tensor")
+        place = core.CPUPlace()
+        tensor = var.get_tensor()
+        tensor.set_dims([5, 2, 3, 4])
+        tensor.alloc_float(place)
+        tensor_array = numpy.array(tensor)
+        tensor_array[0, 0, 0, 0] = 1.0
+        tensor_array[0, 0, 0, 1] = 2.0
+        tensor.set(tensor_array, place)
+        lod_py = [[0, 2, 5], [0, 2, 4, 5]]
+
+        lod_tensor = core.LoDTensor(lod_py, tensor)
+        lod_v = numpy.array(lod_tensor.tensor())
+        self.assertAlmostEqual(1.0, lod_v[0, 0, 0, 0])
+        self.assertAlmostEqual(2.0, lod_v[0, 0, 0, 1])
+        self.assertListEqual(lod_py, lod_tensor.lod())
+
 
 if __name__ == '__main__':
     unittest.main()