1. Example, BP learning function XOR
Training samples (bipolar)
Network: with thresholds (fixed output 1)
Initial weights W(0)
Learning rate = 0.2
Node function: hyperbolic tangent
in_1
in_2 d P0 -1 P1 1 P2 P3 pj
W(1,0)
W(2,1) o 2 1

4. MSE reduction: every 10 epochs Output: every 10 epochs P0 P1 P2 p3 MSE20 40 90
140
190 d P0
-0.63
-0.05
-0.38
-0.77
-0.89
-0.92
-0.93 -1 P1
-0.08
0.23
0.68
0.85
0.89
0.90 P2
-0.62
-0.16
0.15 p3
0.03
-0.37
MSE
1.44
1.12
0.52
0.074
0.019
0.010
0.007

5. After epoch 1 init p0 p1 p2 p3 # epoch (-0.5, 0.5, -0.5)
(-0.5, -0.5, 0.5)
(-1, 1, 1) p0
, ,
, ,
, , p1
, ,
, ,
, , p2
, ,
, ,
, , p3
, ,
, ,
, ,
# epoch 13
, ,
, ,
0.6917, , 40
, ,
, ,
1.9870, , 90
, ,
, ,
2.7061, ,
190
, ,
, ,
3.1995, ,