/// <param name="TargetGraph">
/// Undirected web graph where the RWR will be calculated.
/// </param>
/// <param name="DampingFactor">
/// The damping factor alpha.
/// </param>
/// <param name="InitialNode">
/// List of initial nodes whose initial score set to be 1 and all others 0.
/// </param>
/// <param name="T">
/// Error tolerance.
/// </param>
public SignedRWR(WeightedUndirectedGraph TargetGraph, double DampingFactor, int InitialNode, double T, double beta, double gamma)
{
this.D = DampingFactor;
this.graph = TargetGraph;
this.T = T;
this.beta = beta;
this.gamma = gamma;
score = new double[graph.Size];
nscore = new double[graph.Size];
pscore = new double[graph.Size];
restart = new double[graph.Size];
for (int i = 0; i < score.Length; i++)
{
if (InitialNode == i)
{
pscore[i] = 1.0d;
nscore[i] = 0.0d;
restart[i] = 1.0d;
score[i] = pscore[i] - nscore[i];
}
else
{
pscore[i] = 0.0d;
nscore[i] = 0.0d;
score[i] = pscore[i] - nscore[i];
restart[i] = 0.0d;
}
}
}
public override void Recommend()
{
// RWR 점수 계산
recommend_user_item = new Dictionary <int, List <Score> >();
// 그래프 모델링 및 분석
WeightedUndirectedGraph model_graph = new WeightedUndirectedGraph(links, e);
user_size = model_graph.user_size;
for (int i = 1; i < user_size; i++)
{
// 해당 사용자가 test user가 아니면 스킵
if (!correct_user_item.ContainsKey(i))
{
continue;
}
else if (i % 50 == 0)
{
Console.WriteLine("{0} Recommendation: user {1} / {2}", fold, i, (user_size - 1));
}
List <Score> recommend_items = PerformRWR(model_graph, i);
recommend_user_item.Add(i, recommend_items);
}
Console.WriteLine("Compute RWR scores of {0}: Complete", fold);
}
public override void Recommend()
{
// RWR 점수 계산
recommend_user_item = new ConcurrentDictionary <int, List <Score> >();
Stopwatch sw = new Stopwatch();
sw.Start();
// 그래프 모델링 및 분석
WeightedUndirectedGraph model_graph = new WeightedUndirectedGraph(links, e, num_user, balance);
sw.Stop();
Console.WriteLine("Complete 'links to graph'");
TimeSpan ts = sw.Elapsed;
// Format and display the TimeSpan value.
string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10);
Console.WriteLine("RunTime : " + elapsedTime);
user_size = model_graph.user_size;
sw.Start();
model_graph.CreateAdjacencyMatrx();
sw.Stop();
Console.WriteLine("Complete 'graph to matrix'");
ts = sw.Elapsed;
elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10);
Console.WriteLine("RunTime : " + elapsedTime);
Console.WriteLine("dangling node's Count: {0}", model_graph.dangling_node.Count);
Console.WriteLine("global_p's count: {0}", model_graph.global_p.Count);
Console.WriteLine("global_n's count: {0}", model_graph.global_n.Count);
sw.Start();
int testCount = correct_user_item.Keys.Count();
int ff = 0;
Parallel.For(0, user_size, (i) =>
{
if (correct_user_item.ContainsKey(i))
{
Interlocked.Increment(ref ff);
Console.WriteLine("user id " + i + " 's rec started, (" + ff + "/" + testCount + ")");
List <Score> recommend_items = PerformRWR(model_graph, i);
recommend_user_item.TryAdd(i, recommend_items);
}
});
Console.WriteLine("Compute RWR scores of {0}: Complete", fold);
sw.Stop();
ts = sw.Elapsed;
elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10);
Console.WriteLine("RunTime : " + elapsedTime);
}
/// <summary>
/// user-item 형태로 모델링된 bipartite graph를 사용하여 모든 test user에 대해 RWR 수행
/// </summary>
/// <param name="model_graph">user-item에 대한 bipartite graph</param>
/// <param name="sw">추천 결과(사용자 id, 아이템 id, 점수)가 출력될 파일</param>
public List <Score> PerformRWR(WeightedUndirectedGraph model_graph, int target)
{
// test user가 기존에 갖고 있는 이력 리스트를 저장
HashSet <int> i_items = new HashSet <int>();
if (model_graph.graph.ContainsKey(target))
{
HashSet <Weight> i_weight = model_graph.graph[target];
foreach (Weight items in i_weight)
{
i_items.Add(items.id);
}
}
// RWR 수행
RWR ranker = new RWR(model_graph, damping_factor, target);
List <Weight> score = ranker.Calculate();
// RWR 점수를 기준으로 타겟 사용자가 선호할 만한 TOP N개의 아이템 출력
List <Score> recommend_items = new List <Score>();
//Dictionary<int, double> recommend_items = new Dictionary<int, double>();
foreach (Weight s in score)
{
// ID가 user ID 이거나, 추천 아이템이 타겟 사용자의 기존 이력에 포함되어 있으면 TOP N에 포함시키지 않음
if (s.id < user_size || i_items.Contains(s.id))
{
continue;
}
else if (recommend_items.Count < num_recommend)
{
if (candidate_item == "Longtail_items")
{
if (Program.tophead_items.Contains(s.id))
{
continue;
}
}
Score user_score = new Score(s.id, s.w);
recommend_items.Add(user_score);
}
else
{
break;
}
}
return(recommend_items);
}
public Dictionary <int, double> PerformRWR(WeightedUndirectedGraph model_graph, int target)
{
HashSet <int> i_items = new HashSet <int>();
if (model_graph.graph.ContainsKey(target))
{
SortedSet <Weight> i_weight = model_graph.graph[target];
foreach (Weight items in i_weight)
{
i_items.Add(items.id);
}
}
RWR ranker = new RWR(model_graph, damping_factor, target);
List <Weight> score = ranker.Calculate();
double sum = 0d;
Dictionary <int, double> recommend_items = new Dictionary <int, double>();
foreach (Weight s in score)
{
if (s.id >= user_size)
{
sum += s.w;
}
}
foreach (Weight s in score)
{
if (s.id < user_size || i_items.Contains(s.id))
{
continue;
}
if (candidate_item == "Longtail_items")
{
if (Program.tophead_items.Contains(s.id))
{
continue;
}
}
recommend_items.Add(s.id, s.w / sum);
}
return(recommend_items);
}
/// <param name="TargetGraph">
/// Undirected web graph where the RWR will be calculated.
/// </param>
/// <param name="DampingFactor">
/// The damping factor alpha.
/// </param>
/// <param name="InitialNode">
/// List of initial nodes whose initial score set to be 1 and all others 0.
/// </param>
/// <param name="T">
/// Error tolerance.
/// </param>
public SignedRWR(WeightedUndirectedGraph TargetGraph, double DampingFactor, int InitialNode, double T, double beta, double gamma, double delta)
{
this.D = DampingFactor;
this.graph = TargetGraph;
this.T = T;
this.beta = beta;
this.gamma = gamma;
this.delta = delta;
this.user_size = TargetGraph.user_size;
this.cs = new int[8];
for (int i = 0; i < 8; i++)
{
cs[i] = 0;
}
score = new double[graph.user_size];
pscore = new double[graph.user_size];
nscore = new double[graph.user_size];
//pscore = Vector.Create<double>(graph.Size);
//nscore = Vector.Create<double>(graph.Size);
init_node = InitialNode;
for (int i = 0; i < score.Length; i++)
{
if (InitialNode == i)
{
pscore[i] = 1.0d;
nscore[i] = 0.0d;
score[i] = pscore[i] - nscore[i];
}
else
{
pscore[i] = 0.0d;
nscore[i] = 0.0d;
score[i] = pscore[i] - nscore[i];
}
}
u_global_val = 1 / (double)(2 * graph.user_size);
//i_global_val = 1 / (double)(2 * this.user_size);
}
public RWR(WeightedUndirectedGraph TargetGraph, double DampingFactor, int InitialNode, double T)
{
this.D = DampingFactor;
this.graph = TargetGraph;
this.T = T;
score = new double[graph.user_size];
restart = new double[graph.user_size];
for (int i = 0; i < score.Length; i++)
{
if (InitialNode == i)
{
score[i] = 1.0d;
restart[i] = 1.0d;
}
else
{
score[i] = 0.0d;
restart[i] = 0.0d;
}
}
}
public override void Recommend()
{
// RWR scores
recommend_user_item = new Dictionary <int, List <Score> >();
WeightedUndirectedGraph positive_graph = new WeightedUndirectedGraph(links_like, e);
WeightedUndirectedGraph negative_graph = new WeightedUndirectedGraph(links_dislike, e);
user_size = positive_graph.user_size;
for (int i = 1; i < user_size; i++)
{
if (!correct_user_item.ContainsKey(i))
{
continue;
}
else if (i % 50 == 0)
{
Console.WriteLine("{0} Recommendation: user {1} / {2}", fold, i, (user_size - 1));
}
Dictionary <int, double> like_items = PerformRWR(positive_graph, i);
Dictionary <int, double> dislike_items = PerformRWR(negative_graph, i);
double dislike_min = 1d;
foreach (int item_id in dislike_items.Keys)
{
if (dislike_items[item_id] == 0)
{
continue;
}
if (dislike_min > dislike_items[item_id])
{
dislike_min = dislike_items[item_id];
}
}
List <Score> recommend_items = new List <Score>();
foreach (int item_id in like_items.Keys)
{
double final = 0d;
if (!dislike_items.ContainsKey(item_id))
{
continue;
}
else if (dislike_items[item_id] == 0)
{
final = like_items[item_id] - dislike_min;
}
else
{
final = like_items[item_id] - dislike_items[item_id];
}
Score user_score = new Score(item_id, final);
recommend_items.Add(user_score);
}
recommend_items.Sort(Score.CompareScore);
recommend_user_item.Add(i, recommend_items);
}
Console.WriteLine("Compute RWR scores of {0}: Complete", fold);
}
public RWR(WeightedUndirectedGraph TargetGraph, double DampingFactor, int InitialNode)
: this(TargetGraph, DampingFactor, InitialNode, -1)
{
}
/// <param name="TargetGraph">
/// Undirected web graph where the RWR will be calculated.
/// </param>
/// <param name="DampingFactor">
/// The damping factor alpha.
/// </param>
/// <param name="InitialNode">
/// List of initial nodes whose initial score set to be 1 and all others 0.
/// </param>
public SignedRWR(WeightedUndirectedGraph TargetGraph, double DampingFactor, int InitialNode, double beta, double gamma, double delta)
: this(TargetGraph, DampingFactor, InitialNode, -1, beta, gamma, delta)
{
}
