diff --git a/.gitignore b/.gitignore
index 21229f7..21649bb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
-*.asv
\ No newline at end of file
+*.asv
+*.mexw32
+*.mat
\ No newline at end of file
diff --git a/UserSum.c b/UserSum.c
new file mode 100644
index 0000000..b7f0e25
--- /dev/null
+++ b/UserSum.c
@@ -0,0 +1,62 @@
+#include "mex.h"
+#include "math.h"
+typedef unsigned int size_t;
+
+void mexFunction(int nlhs, mxArray* plhs[],int nrhs, const mxArray* prhs[])
+{
+    size_t Alen=0;
+    size_t Blen=0;
+    size_t i=0;
+    double *dataA=NULL;
+    double *dataB=NULL;
+    double sum=0;
+    mxArray *pSum=NULL;
+    if(nrhs<2)
+    {
+        mexPrintf("parameters are fewer than 2\n");
+        plhs=NULL;
+        nlhs=0;
+        return;
+    }
+    Alen=length(prhs[0]);
+    Blen=length(prhs[1]);
+    if(Alen!=Blen)
+    {
+        mexPrintf("dim of para inconsists.\n");
+        return;
+    }
+//     mexPrintf("A %d B %d\n",Alen,Blen);
+    dataA=mxGetPr(prhs[0]);
+    dataB=mxGetPr(prhs[1]);
+//     mexPrintf("%f\n",dataA[0]);
+    for(i=0;i<Alen;i++)
+    {
+        sum+=pow(dataA[i]-dataB[i],2);
+    }
+    sum=sqrt(sum);
+    pSum=mxCreateScalarDouble(sum);
+    if(nlhs>0)
+    {
+        plhs[0]=pSum;
+    }
+    else
+    {
+        mexPrintf("must have at least one out para.\n");
+        return;
+    }
+    
+}
+
+size_t length(const mxArray* p)
+{
+    size_t m=0;
+    size_t n=0;
+    m=mxGetM(p);
+    n=mxGetN(p);
+    if(m>n)
+    {
+        return m;
+    }
+    return n;
+}
+
diff --git a/main.m b/main.m
index d9123b4..a32ef0c 100644
--- a/main.m
+++ b/main.m
@@ -44,6 +44,7 @@ for clusterI=1:clusterN-1
             
 %             distanceIJ=sum((d-data(:,cddtI)).^2).^.5;
             distanceIJ=metricFun( d,data(:,cddtI) );
+%             distanceIJ_t=UserSum(d,data(:,cddtI));
             Cij=Cij+max([minD-distanceIJ,0]);
         end
         maxG(cluster)=Cij;
@@ -73,13 +74,15 @@ while 1
                 if J==cadSetS(I)
                     continue
                 end
+                
                 matDistance=repmat(d,1,length(SetS));
                 minD=matDistance-data(:,SetS);
                 minD=diag(minD'*minD).^.5;
                 minD_t=min(minD);
                 minD(minD==minD_t)=1e20;
                 min2D=min(minD);
-                minD=minD_t;            
+                minD=minD_t; 
+                
 %                 distanceIJ=sum((d-data(:,cadUSetS(H))).^2).^.5;%S(I)ÒѾ­µÈÓÚU(H)
                 distanceIJ=metricFun( d,data(:,cadUSetS(H)) );
 %                 distanceHJ=sum((d-data(:,cadSetS(I))).^2).^.5;
diff --git a/metricFun.m b/metricFun.m
index 708660e..a97a59d 100644
--- a/metricFun.m
+++ b/metricFun.m
@@ -1,6 +1,7 @@
 function [ output_args ] = metricFun( a,b )
-output_args=sum((a-b).^2).^.5;
+% output_args=sum((a-b).^2).^.5;
 % output_args=(a-b)'*(a-b);
 % output_args=sum(abs(a-b));
+output_args=UserSum(a,b);
 end