From 569616b329db71bfc4739021d55e0a74179732e2 Mon Sep 17 00:00:00 2001
From: Yu Yang <yuyang18@baidu.com>
Date: Mon, 9 Oct 2017 14:04:36 -0700
Subject: [PATCH] Complete Variable for Python API

---
 python/paddle/v2/framework/graph.py           | 59 ++++++++++++++++---
 .../v2/framework/tests/test_variable.py       | 20 ++++++-
 2 files changed, 71 insertions(+), 8 deletions(-)

diff --git a/python/paddle/v2/framework/graph.py b/python/paddle/v2/framework/graph.py
index a7a3ca62c7f..a66e7a9d731 100644
--- a/python/paddle/v2/framework/graph.py
+++ b/python/paddle/v2/framework/graph.py
@@ -12,23 +12,68 @@ class Variable(object):
 
         if name is None:
             name = Variable._unique_var_name_()
-        self.proto = self.block.proto.new_var(name)
+        try:
+            self.proto = self.block.proto.var(name)
+            is_new_var = False
+        except core.EnforceNotMet:
+            self.proto = self.block.proto.new_var(name)
+            is_new_var = True
 
         if shape is not None:
-            self.proto.set_shape(shape)
-
+            if is_new_var:
+                self.proto.set_shape(shape)
+            else:
+                old_shape = self.shape
+                shape = tuple(shape)
+                if shape != old_shape:
+                    raise ValueError(
+                        "Variable {0} has been created before. the previous "
+                        "shape is {1}; the new shape is {2}. They are not "
+                        "matched.".format(self.name, old_shape, shape))
         if dtype is not None:
             if not isinstance(dtype, core.DataType):
                 dtype = Variable._convert_np_dtype_to_dtype_(dtype)
-            self.proto.set_data_type(dtype)
+            if is_new_var:
+                self.proto.set_data_type(dtype)
+            else:
+                old_dtype = self.data_type()
+                if dtype != old_shape:
+                    raise ValueError("Variable {0} has been created before. "
+                                     "The previous data type is {1}; the new "
+                                     "data type is {2}. They are not "
+                                     "matched.".format(self.name, old_dtype,
+                                                       dtype))
 
         if lod_level is not None:
-            self.proto.set_lod_level(lod_level)
+            if is_new_var:
+                self.proto.set_lod_level(lod_level)
+            else:
+                if lod_level != self.lod_level:
+                    raise ValueError("Variable {0} has been created before. "
+                                     "The previous lod_level is {1}; the new "
+                                     "lod_level is {2}. They are not "
+                                     "matched".format(self.name, self.lod_level,
+                                                      lod_level))
 
         self.block.vars[name] = self
         self.op = None
 
-    # TODO(yuyang18): Get methods
+    @property
+    def name(self):
+        return self.proto.name()
+
+    @property
+    def shape(self):
+        # convert to tuple, make it as same as numpy API.
+        return tuple(self.proto.shape())
+
+    @property
+    def data_type(self):
+        return self.proto.data_type()
+
+    @property
+    def lod_level(self):
+        return self.proto.lod_level()
 
     @staticmethod
     def _unique_var_name_():
@@ -79,7 +124,7 @@ class Operator(object):
             # TODO
             pass
 
-        # TODO: Getters
+            # TODO: Getters
 
 
 class Block(object):
diff --git a/python/paddle/v2/framework/tests/test_variable.py b/python/paddle/v2/framework/tests/test_variable.py
index dd23eac0cd1..8ea1083ff65 100644
--- a/python/paddle/v2/framework/tests/test_variable.py
+++ b/python/paddle/v2/framework/tests/test_variable.py
@@ -1,5 +1,5 @@
 import unittest
-from paddle.v2.framework.graph import Variable
+from paddle.v2.framework.graph import Variable, g_program
 import paddle.v2.framework.core as core
 import numpy as np
 
@@ -17,6 +17,24 @@ class TestVariable(unittest.TestCase):
         self.assertEqual(DT.BOOL, convert("bool"))
         self.assertRaises(ValueError, lambda: convert("int8"))
 
+    def test_var(self):
+        b = g_program.current_block()
+        w = b.create_var(
+            dtype="float64", shape=[784, 100], lod_level=0, name="fc.w")
+        self.assertEqual(core.DataType.FP64, w.data_type)
+        self.assertEqual((784, 100), w.shape)
+        self.assertEqual("fc.w", w.name)
+        self.assertEqual(0, w.lod_level)
+
+        w = b.create_var(name='fc.w')
+        self.assertEqual(core.DataType.FP64, w.data_type)
+        self.assertEqual((784, 100), w.shape)
+        self.assertEqual("fc.w", w.name)
+        self.assertEqual(0, w.lod_level)
+
+        self.assertRaises(ValueError,
+                          lambda: b.create_var(name="fc.w", shape=(24, 100)))
+
 
 if __name__ == '__main__':
     unittest.main()
-- 
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