Question

我正在调整https://github.com/466152112/HappyResearch/blob/master/happyresearch/src/main/java/happy/research/utils/MoleTrust.java的Moletrust算法实现的开源代码我应该为计算信任值而做出的改变改编自本文由Moletrust创建者编写的“推荐系统的信任感知协同过滤”。他们按如下方式计算信任 “距离源用户距离为n的用户将具有预测的信任值（d-n + 1）/ d”，其中d是最大传播距离。我得到的结果是1或0，这是不正确的。希望你能帮我找到错误。

public static HashMap<String ,Double> MoleTrustAlg ( HashMap<String,HashMap<String,Double>> trust_data,String sourceUser , int horizon)
{
    // all the visited nodes 
    List<String> nodes = new ArrayList<>(40163); 
    // source user - edges[target users - trust value] 
    Map<String, Map<String, Double>> edges = new HashMap<>(40163); 

    /* Step 1: construct directed graphic and remove cyclic */ 
    int dist = 0; 
    List<String>[] users = new List[horizon + 1]; 
    users[dist] = new ArrayList<>(); 
    users[dist].add(sourceUser); 
    nodes.add(sourceUser); 

    // Denote su: source user; tu: target user 
    while (dist < horizon) 
    { 
        dist++; 
        users[dist] = new ArrayList<>(); 
        for (String su : users[dist - 1]) 
        { 
            Map<String, Double> tns = trust_data.get(su); 
            if (tns == null) continue; // no trusted neighbours 
            for (String tn : tns.keySet()) 
            { 
                if (!nodes.contains(tn) && !users[dist].contains(tn) && !users[dist - 1].contains(tn)) 
                { 
                    users[dist].add(tn); 
                } 
            } 
        } 

        for (String su : users[dist - 1]) 
        { 
            Map<String, Double> tns = trust_data.get(su); 
            if (tns == null) continue; 
            for (String tu : tns.keySet()) 
            { 
                if (!nodes.contains(tu) && users[dist].contains(tu)) 
                { 
                    Map<String, Double> tuTrusts; 
                    if (edges.containsKey(su)) tuTrusts = edges.get(su); 
                    else tuTrusts = new HashMap<>(); 

                    double trustValue = tns.get(tu); 
                    tuTrusts.put(tu, trustValue); 
                    edges.put(su, tuTrusts); 
                } 
            } 
        } 
    } 

    /* Step 2: Evaluate trust score */ 
    dist = 0; 
    //double threashold = 0.5; 
    // trusted neighbours - trust score map 
    HashMap<String, Double> trustScores = new HashMap<>(); 
    trustScores.put(sourceUser, 1.0); 
    while (dist < horizon) 
    { 
        dist++;
        for (String su : users[dist - 1]) 
        { 
            Map<String, Double> tns = trust_data.get(su); 
            if (tns == null) continue; 
            for (String tu : tns.keySet()) 
            {

                double trust_value = (horizon -dist +1) / horizon;
                trustScores.put(tu, trust_value);
            }
        }

    } 

    trustScores.remove(sourceUser); 
    return trustScores; 
}

Answer 1

GOT IT

原因是 double trust_value =（horizon -dist +1）/ horizon;

因为horizon和dist是整数，我需要在将结果赋值给double变量之前进行转换 double trust_value =（double）（horizon -dist +1）/ horizon;

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1 个答案: