gpus = tf.config.list_physical_devices('GPU')
if gpus:
  try:
    # Currently, memory growth needs to be the same across GPUs
    for gpu in gpus:
      tf.config.experimental.set_memory_growth(gpu, True)
  except RuntimeError as e:
    # Memory growth must be set before GPUs have been initialized
    print(e)

Its stated in https://www.tensorflow.org/guide/gpu