//--------------------------------------------------------------------------------------- //This function computes the DISTANCE matrix and inserts it into the database //This is the distance between the two columns of the Rating Matrix //Created by Vuong Minh Tuan //Corrected all errors by MC. NGUYEN 21.10.2014. //--------------------------------------------------------------------------------------- public void ComputeDIST(Predict_DAO_MC dao) { dao.CLEAN_DIST_Matrix(); List<string> list_ClusterID = dao.getAllClusterID(); foreach (var item in list_ClusterID) { Dictionary<string, int> RM_dic_users = new Dictionary<string, int>(); Dictionary<string, int> RM_dic_items = new Dictionary<string, int>(); // Compute ratting matrix List<MatrixItem> lstRMI = dao.getRattingMatrixItem_ByClusterID(item); double[][] RattingMatrix = Util.toMatrix_MatrixItem(lstRMI, out RM_dic_users, out RM_dic_items); if (RattingMatrix.Length > 0 & RM_dic_items.Count > 1) { double[][] DIST = new double[RattingMatrix[0].Length][]; for (int i = 0; i < RattingMatrix[0].Length; i++) DIST[i] = new double[RattingMatrix[0].Length]; // Compute DIST Matrix for (int i1 = 0; i1 < RattingMatrix[0].Length - 1; i1++) for (int i2 = i1 + 1; i2 < RattingMatrix[0].Length; i2++) { double value = 0.0; for (int t = 0; t < RattingMatrix.Length; t++) value += Math.Pow(RattingMatrix[t][i1] - RattingMatrix[t][i2], 2); value = Math.Sqrt(value); DIST[i1][i2] = value; DIST[i2][i1] = value; } if (DIST.Length > 0) { double max = DIST[0][0]; // Find Max for (int i = 0; i < DIST.Length; i++) { double localMax = DIST[i].Max(); if (localMax > max) max = localMax; } // Standardization if (max != 0) { for (int i = 0; i < DIST.Length; i++) for (int j = 0; j < DIST[0].Length; j++) DIST[i][j] /= max; } // Save to Database for (int i = 0; i < DIST.Length; i++) for (int j = 0; j < DIST[0].Length; j++) if (DIST[i][j] > 0) { MatrixItem matrixItem = new MatrixItem(); matrixItem.Row = Util.FindKeyByValue(RM_dic_items, i); matrixItem.Column = Util.FindKeyByValue(RM_dic_items, j); matrixItem.Cell = DIST[i][j]; matrixItem.ClusterID = item; dao.setDIST_Matrix(matrixItem); } } } } }