Add convert function

paddle/parameter/tests/test_argument.cpp

@@ -42,7 +42,7 @@ TEST(Argument, poolSequenceWithStride) {
     CHECK_EQ(outStart[3], 4);
     CHECK_EQ(outStart[4], 7);
 
-    CHECK_EQ(stridePositions->getSize(), 8);
+    CHECK_EQ(stridePositions->getSize(), 8UL);
     auto result = reversed ? strideResultReversed : strideResult;
     for (int i = 0; i < 8; i++) {
       CHECK_EQ(stridePositions->getData()[i], result[i]);

python/paddle/v2/dataset/common.py

@@ -149,3 +149,57 @@ def reader():
                     yield line
 
     return reader
+
+
+def convert(output_path,
+            reader,
+            num_shards,
+            name_prefix,
+            max_lines_to_shuffle=1000):
+    import recordio
+    import cPickle as pickle
+    import random
+    """
+    Convert data from reader to recordio format files.
+
+    :param output_path: directory in which output files will be saved.
+    :param reader: a data reader, from which the convert program will read data instances.
+    :param num_shards: the number of shards that the dataset will be partitioned into.
+    :param name_prefix: the name prefix of generated files.
+    :param max_lines_to_shuffle: the max lines numbers to shuffle before writing.
+    """
+
+    assert num_shards >= 1
+    assert max_lines_to_shuffle >= 1
+
+    def open_writers():
+        w = []
+        for i in range(0, num_shards):
+            n = "%s/%s-%05d-of-%05d" % (output_path, name_prefix, i,
+                                        num_shards - 1)
+            w.append(recordio.writer(n))
+
+        return w
+
+    def close_writers(w):
+        for i in range(0, num_shards):
+            w[i].close()
+
+    def write_data(w, lines):
+        random.shuffle(lines)
+        for i, d in enumerate(lines):
+            d = pickle.dumps(d, pickle.HIGHEST_PROTOCOL)
+            w[i % num_shards].write(d)
+
+    w = open_writers()
+    lines = []
+
+    for i, d in enumerate(reader()):
+        lines.append(d)
+        if i % max_lines_to_shuffle == 0 and i >= max_lines_to_shuffle:
+            write_data(w, lines)
+            lines = []
+            continue
+
+    write_data(w, lines)
+    close_writers(w)

python/paddle/v2/dataset/tests/common_test.py

@@ -57,6 +57,38 @@ def test_cluster_file_reader(self):
         for idx, e in enumerate(reader()):
             self.assertEqual(e, str("0"))
 
+    def test_convert(self):
+        record_num = 10
+        num_shards = 4
+
+        def test_reader():
+            def reader():
+                for x in xrange(record_num):
+                    yield x
+
+            return reader
+
+        path = tempfile.mkdtemp()
+        paddle.v2.dataset.common.convert(path,
+                                         test_reader(), num_shards,
+                                         'random_images')
+
+        files = glob.glob(path + '/random_images-*')
+        self.assertEqual(len(files), num_shards)
+
+        recs = []
+        for i in range(0, num_shards):
+            n = "%s/random_images-%05d-of-%05d" % (path, i, num_shards - 1)
+            r = recordio.reader(n)
+            while True:
+                d = r.read()
+                if d is None:
+                    break
+                recs.append(d)
+
+        recs.sort()
+        self.assertEqual(total, record_num)
+
 
 if __name__ == '__main__':
     unittest.main()