AffineTransformation.cs

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// TraceLab Component Library
// Copyright © 2012-2013 SEMERU
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using TraceLab.Components.DevelopmentKit.Utils;
using TraceLabSDK.Types;

namespace TraceLab.Components.DevelopmentKit.Postprocessors
{
    public static class AffineTranformation
    {
        public static TLSimilarityMatrix Transform(TLSimilarityMatrix large, TLSimilarityMatrix small, double lambda)
        {
            TLSimilarityMatrix largeNormal = Normalize(large);
            TLSimilarityMatrix smallNormal = Normalize(small);
            TLSimilarityMatrix combined = new TLSimilarityMatrix();

            foreach (TLSingleLink largeLink in largeNormal.AllLinks)
            {
                double smallLink = smallNormal.GetScoreForLink(largeLink.SourceArtifactId, largeLink.TargetArtifactId);
                combined.AddLink(largeLink.SourceArtifactId, largeLink.TargetArtifactId, Combine(largeLink.Score, smallLink, lambda));
            }

            return combined;
        }

        public static double Combine(double large, double small, double lambda)
        {
            return (lambda * large) + ((1 - lambda) * small);
        }

        public static TLSimilarityMatrix Normalize(TLSimilarityMatrix matrix)
        {
            TLSimilarityMatrix norm = new TLSimilarityMatrix();
            double mean = TLSimilarityMatrixUtil.AverageSimilarity(matrix);
            double stdDev = TLSimilarityMatrixUtil.SimilarityStandardDeviation(matrix);
            foreach (TLSingleLink link in matrix.AllLinks)
            {
                norm.AddLink(link.SourceArtifactId, link.TargetArtifactId, (link.Score - mean) / stdDev);
            }
            return norm;
        }
    }
}