more things to add

Signed-off-by: szalpal <mszolucha@nvidia.com>

dali/python/nvidia/dali/pipeline.py

@@ -51,10 +51,13 @@ class Pipeline(object):
 Parameters
 ----------
 `batch_size` : int, optional, default = -1
-    Batch size of the pipeline. Negative values for this parameter
+    Maximum batch size of the pipeline. Negative values for this parameter
     are invalid - the default value may only be used with
     serialized pipeline (the value stored in serialized pipeline
-    is used instead).
+    is used instead). In most cases, the actual batch size of the pipeline
+    will be equal to the maximum one. Running DALI pipeline with batch size
+    smaller than that is supported. Batch size might change from iteration
+    to iteration of DALI pipeline.
 `num_threads` : int, optional, default = -1
     Number of CPU threads used by the pipeline.
     Negative values for this parameter are invalid - the default

dali/test/python/test_external_source_impl.py

@@ -416,26 +416,6 @@ def iter_setup(self):
             break
     assert(iter_num == i)
 
-def test_external_source_fail():
-    class ExternalSourcePipeline(Pipeline):
-        def __init__(self, batch_size, external_s_size, num_threads, device_id):
-            super(ExternalSourcePipeline, self).__init__(batch_size, num_threads, device_id)
-            self.input = ops.ExternalSource()
-            self.batch_size_ = batch_size
-            self.external_s_size_ = external_s_size
-
-        def define_graph(self):
-            self.batch = self.input()
-            return [self.batch]
-
-        def iter_setup(self):
-            batch = datapy.zeros([self.external_s_size_,4,5])
-            self.feed_input(self.batch, batch)
-
-    batch_size = 3
-    pipe = ExternalSourcePipeline(batch_size, batch_size - 1, 3, 0)
-    pipe.build()
-    assert_raises(RuntimeError, pipe.run)
 
 def test_external_source_fail_missing_output():
     class ExternalSourcePipeline(Pipeline):
@@ -461,28 +441,6 @@ def iter_setup(self):
     pipe.build()
     assert_raises(RuntimeError, pipe.run)
 
-def test_external_source_fail_list():
-    class ExternalSourcePipeline(Pipeline):
-        def __init__(self, batch_size, external_s_size, num_threads, device_id):
-            super(ExternalSourcePipeline, self).__init__(batch_size, num_threads, device_id)
-            self.input = ops.ExternalSource()
-            self.batch_size_ = batch_size
-            self.external_s_size_ = external_s_size
-
-        def define_graph(self):
-            self.batch = self.input()
-            return [self.batch]
-
-        def iter_setup(self):
-            batch = []
-            for _ in range(self.external_s_size_):
-                batch.append(datapy.zeros([3,4,5]))
-            self.feed_input(self.batch, batch)
-
-    batch_size = 3
-    pipe = ExternalSourcePipeline(batch_size, batch_size - 1, 3, 0)
-    pipe.build()
-    assert_raises(RuntimeError, pipe.run)
 
 def external_data_veri(external_data, batch_size):
     class ExternalSourcePipeline(Pipeline):