#-------------------------------------------------------------
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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.
#
#-------------------------------------------------------------

# Returns the peak signal to noise ratio
#
# https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio
#
# INPUT:
# --------------------------------------------------------------------------------
# X      First Matrix to compare
# Y      Second Matrix to compare
# --------------------------------------------------------------------------------
#
# OUTPUT:
# -----------------------------------------------------------------------------------------------
# Z      The peak signal to noise ratio
# -----------------------------------------------------------------------------------------------

m_psnr = function(Matrix[Double] X, Matrix[Double] Y) return (Matrix[Double] Z) {
  [MSE, NN] = mse(X=X, Y=Y)
  Z = 10 * log(max(X)^2 / MSE, 10)
}