Add model_helpers.py to repo which can be used by all video frame prediction models.

video_prediction_tools/model_modules/video_prediction/models/model_helpers.py

+__email__ = "b.gong@fz-juelich.de"
+__author__ = "Bing Gong, Michael Langguth"
+__date__ = "2021-20-05"
+
+"""
+Some auxiliary functions that can be used by any video prediction model
+"""
+
+
+def set_and_check_pred_frames(seq_length, context_frames):
+    """
+    Checks if sequence length and context_frames are set properly and returns number of frames to be predicted.
+    :param seq_length: number of frames/images per sequences
+    :param context_frames: number of context frames/images
+    :return: number of predicted frames
+    """
+
+    method = set_and_check_pred_frames.__name__
+
+    # sanity checks
+    assert isinstance(seq_length, int), "%{0}: Sequence length (seq_length) must be an integer".format(method)
+    assert isinstance(context_frames, int), "%{0}: Number of context frames must be an integer".format(method)
+
+    if seq_length > context_frames:
+        return seq_length - context_frames
+    else:
+        raise ValueError("%{0}: Sequence length ({1}) must be larger than context frames ({2})."
+                         .format(method, seq_length, context_frames))
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