Added files via upload

Author: hanwangzhang

DCF.m

@@ -1,5 +1,5 @@
 function [B,D,X,Y] = DCF(maxS, minS, S, ST, IDX, IDXT, r, alpha, beta, option)
-%DCF: Dicrete Collaborative Filtering as
+%DCF: Dicrete Collaborative Filtering described in Algorithm 1.
 
 %Input:
 %maxS: max rating score

DCFinit.m

@@ -1,5 +1,5 @@
 function [U,V,X,Y] = DCFinit(maxS, minS, S, ST, IDX, IDXT, r, alpha, beta, option)
-%DCFinit: Initialization for Dicrete Collaborative Filtering as in Eq.(22)
+%DCFinit: Initialization for Dicrete Collaborative Filtering as in Eq.(17)
 
 %Input:
 %maxS: max rating score

test.m

@@ -6,7 +6,9 @@
 S = S*5;
 S = ceil(S);
 
-S = sparse(S);
+S = sparse(S);% S should be a sparse matrix in real case.
+%the following transpose is a trick to accelerate sparse matrix
+%indexing in Matlab.
 ST = S';
 IDX = (S~=0);
 IDXT = IDX';