# Copyright 2022 DeepMind Technologies Limited
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================

"""Compute metrics."""
from typing import Sequence

import chex
import jax.numpy as jnp
import numpy as np


def get_compression_rate(images: chex.Array, codes: Sequence[chex.Array],
                         bits_per_element: int) -> float:
  codes_size = np.sum([np.prod(jnp.asarray(code).shape) for code in codes])
  compression_rate = np.prod(images.shape) / codes_size
  bit_ratio = 8 / np.log2(bits_per_element)
  return compression_rate * bit_ratio
