diff --git a/matlab/BeijingPose2Graph_kai.m b/matlab/BeijingPose2Graph_kai.m
new file mode 100644
index 000000000..ab30203f4
--- /dev/null
+++ b/matlab/BeijingPose2Graph_kai.m
@@ -0,0 +1,86 @@
+load beijing.mat;
+load beijing_angles.mat;
+load beijing_graph.mat;
+%load beijing_config.mat;
+
+cov = [ 0.25, 0, 0; 0, 0.25, 0; 0, 0, 0.01];
+
+
+factors = Pose2Graph;
+factors2 = Pose2Graph;
+ord = Ordering();
+ord2 = Ordering();
+
+[~, idx] = sort(way_levels, 'descend');
+
+for i=1:length(idx)
+    if mod(i,500) == 0
+        fprintf(1, 'processing way %d\n', i);
+    end
+    for j=1:length(ways{idx(i)})-1
+        id1 = ways{idx(i)}(j);
+        id2 = ways{idx(i)}(j+1);
+        key1 = sprintf('x%d', id1);
+        key2 = sprintf('x%d', id2);
+
+        delta_x = points(id1,:) - points(id2,:);
+        delta_angle = angles(id1) - angles(id2);
+        measured = Pose2(delta_x(1), delta_x(2), delta_angle);
+
+        if pred(id1) == id2 || pred(id2) == id1 %% in the spanning tree
+            factor=Pose2Factor(key1,key2,measured, cov);
+            factors.push_back(factor);
+            ord.push_back(key1);
+            ord.push_back(key2);
+        else %% not in the spanning tree
+            factors2.push_back(Pose2Factor(key1,key2,measured, cov));
+            ord2.push_back(key1);
+            ord2.push_back(key2);
+        end
+    end
+end
+ord.unique();
+ord2.unique();
+% ord.reverse();
+% ord2.reverse();
+
+if 1
+    config=Pose2Config();
+    n=size(points,1);
+    for j=1:n
+        pose=Pose2(points(j,1),points(j,2),angles(j));
+        key = sprintf('x%d', j);
+        config.insert(key,pose);
+        if mod(j,1000) == 0
+            key
+        end
+    end
+    save('beijing_config.mat','config');
+end
+
+amd_ord=factors.getOrdering_(); % does not work
+LFG=factors.linearize_(config);
+ijs=LFG.sparse(ord);
+A=sparse(ijs(1,:),ijs(2,:),ijs(3,:)); 
+figure(1)
+spy(A);
+%save('beijing_factors.mat', 'factors');
+
+LFG2=factors2.linearize_(config);
+ijs2=LFG2.sparse(ord2);
+A2=sparse(ijs2(1,:),ijs2(2,:),ijs2(3,:)); 
+figure(2)
+spy(A2);
+
+% show R factor
+R = qr(A,0);
+figure(3)
+spy(R)
+
+% show re-ordered R factor
+P = colamd(A);
+figure(4)
+spy(A(:,P))
+R = qr(A(:,P),0);
+figure(5)
+spy(R)
diff --git a/matlab/beijing_graph.mat b/matlab/beijing_graph.mat
index 226272a0a..396fa032d 100644
Binary files a/matlab/beijing_graph.mat and b/matlab/beijing_graph.mat differ