Removed allow_growth and updated docs (#24)

This now allows users to customize this value by setting an environment variable instead of it being hard-coded.

Author: Nikhil1O1

docs/runtime_environment.rst

@@ -56,3 +56,17 @@ Note that non-relative imports to these files will `not` work:
 
    import backend
    from utils import img_utils, ml_utils
+
+Limiting GPU memory Growth
+-----------------------------------------
+
+By default, OpenVisionCapsules maps all available memory of all visible CUDA configured GPUs.
+To prevent this, use following Environment flag while using Tensorflow.
+
+.. code-block:: python
+
+   TF_FORCE_GPU_ALLOW_GROWTH=True
+
+- This Environment variable is only applicable to Tensorflow.
+
+For proper reference, visit Tensorflow: https://www.tensorflow.org/guide/gpu#limiting_gpu_memory_growth

vcap/vcap/device_mapping.py

@@ -29,7 +29,7 @@ def get_all_devices() -> List[str]:
             # TODO: Use tf.config.list_physical_devices in TF 2.1
             # TODO: Remove the config when using TF_FORCE_GPU_ALLOW_GROWTH\
             #  environment variable
-            _process_gpu_options = tf.GPUOptions(allow_growth=True)
+            _process_gpu_options = tf.GPUOptions()
             config = tf.ConfigProto(gpu_options=_process_gpu_options)
 
             with tf.Session(config=config):