@Himanchal Chandra - It is normal to use the lines you mentioned. Why we should use these lines - you may go through the following:

1. https://www.tensorflow.org/api_docs/python/tf/config/experimental/set_memory_growth

2. https://stackoverflow.com/questions/53698035/failed-to-get-convolution-algorithm-this-is-probably-because-cudnn-failed-to-in