#-------------------------------------------------------------
#
# 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
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#
#-------------------------------------------------------------

# Implements builtin for imputing missing values from observed values (if exist) using robust functional dependencies
#
# INPUT:
# --------------------------------------------------------------------------------------
# X          Matrix X
# source     source attribute to use for imputation and error correction
# target     attribute to be fixed
# threshold  threshold value in interval [0, 1] for robust FDs
# --------------------------------------------------------------------------------------
#
# OUTPUT:
# ---------------------------------------------------------------------------------
# X     Matrix with possible imputations
# ---------------------------------------------------------------------------------

m_imputeByFDApply = function(Matrix[Double] X, Matrix[Double] Y_imp)
  return(Matrix[Double] imputed_Y)
{
  X = replace(target = X, pattern=NaN, replacement=1)
  X = replace(target = X, pattern=0, replacement=1)
  imputed_Y = table(seq(1,nrow(X)), X, 1, nrow(X), nrow(Y_imp)) %*% Y_imp;
  imputed_Y = replace(target=imputed_Y, pattern=0, replacement=NaN)
}

