com.simiacryptus.mindseye.art.photo.affinity.RasterAffinity Maven / Gradle / Ivy

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/*
 * Copyright (c) 2019 by Andrew Charneski.
 *
 * The author 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.
 */

package com.simiacryptus.mindseye.art.photo.affinity;

import com.simiacryptus.mindseye.lang.CoreSettings;

import javax.annotation.Nonnull;
import java.util.Arrays;
import java.util.List;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public interface RasterAffinity {
  static List normalize(@Nonnull List graphEdges, @Nonnull List affinityList) {
    return adjust(graphEdges, affinityList, degree(affinityList), 0.5);
  }

  static List adjust(@Nonnull List graphEdges, @Nonnull List affinityList, double[] degree, double power) {
    return IntStream.range(0, graphEdges.size()).mapToObj(i2 -> {
      final double deg_i = degree[i2];
      final int[] edges = graphEdges.get(i2);
      final double[] affinities = affinityList.get(i2);
      if (deg_i == 0)
        return new double[edges.length];
      return IntStream.range(0, edges.length).mapToDouble(j -> {
        final double deg_j = degree[edges[j]];
        if (deg_j == 0)
          return 0;
        return affinities[j] / Math.pow(deg_j * deg_i, power);
      }).toArray();
    }).collect(Collectors.toList());
  }

  static double[] degree(@Nonnull List affinityList) {
    Stream stream = affinityList.stream();
    if (!CoreSettings.INSTANCE().singleThreaded) stream = stream.parallel();
    return stream.mapToDouble(x -> Arrays.stream(x).sum()).toArray();
  }

  @Nonnull
  default AffinityWrapper wrap(@Nonnull BiFunction, List, List> fn) {
    return new AffinityWrapper(this) {
      @Override
      public List affinityList(List graphEdges) {
        return fn.apply(graphEdges, inner.affinityList(graphEdges));
      }
    };
  }

  @Nonnull
  default AffinityWrapper wrap(@Nonnull Function, List> fn) {
    return new AffinityWrapper(this) {
      @Override
      public List affinityList(List graphEdges) {
        return fn.apply(graphEdges);
      }
    };
  }

  List affinityList(List graphEdges);

}