com.tencent.angel.sona.tree.basic.split.SplitSet Maven / Gradle / Ivy

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/*
 * Tencent is pleased to support the open source community by making Angel available.
 *
 * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * 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
 *
 * https://opensource.org/licenses/Apache-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.tencent.angel.sona.tree.basic.split;

import com.tencent.angel.sona.tree.util.MathUtil;

import java.util.Arrays;

public class SplitSet extends SplitEntry {
    private float[] edges;
    private int firstFlow;
    // edges=[x,...] firstFlow=1 => go to left if < x and go to right if > x
    // edges=[x,...] firstFlow=0 => go to right if < x and go to left if > x
    private int defaultFlow;

    public SplitSet() {
        this(-1, 0.0f, null, -1, -1);
    }

    public SplitSet(int fid, float gain, float[] edges, int firstFlow, int defaultFlow) {
        super(fid, gain);
        this.edges = edges;
        this.firstFlow = firstFlow;
        this.defaultFlow = defaultFlow;
    }

    @Override
    public int flowTo(float x) {
        if (x < edges[0] || x > edges[edges.length - 1]) {
            return defaultTo();
        } else if (edges.length == 2) {
            return firstFlow;
        } else {
            int index = MathUtil.indexOf(edges, x);
            if (MathUtil.isEven(index))
                return firstFlow;
            else
                return 1 - firstFlow;
        }
    }

    @Override
    public int defaultTo() {
        return defaultFlow;
    }

    @Override
    public SplitType splitType() {
        return SplitType.SPLIT_SET;
    }

    public float[] getEdges() {
        return edges;
    }

    public int getFirstFlow() {
        return firstFlow;
    }

    @Override
    public String toString() {
        return String.format("%s fid[%d] edges%s firstFlow[%d] defaultFlow[%d] gain[%f]",
                this.splitType(), fid, Arrays.toString(edges), firstFlow, defaultFlow, gain);
    }
}