During training the data , it just change class one accuracy,but the others still show zero

[mciky]

2018-04-23 12:37:04.018255: step 110, loss = 1.55 (7.1 examples/sec; 0.281 sec/batch)
accuracy = 0.999809
mean IU = 0.076908
class # 0 accuracy = 0.999809
class # 1 accuracy = 0.000000
class # 2 accuracy = 0.000000
class # 3 accuracy = 0.000000
class # 4 accuracy = 0.000000
class # 5 accuracy = 0.000000
class # 6 accuracy = 0.000000
class # 7 accuracy = 0.000000
class # 8 accuracy = 0.000000
class # 9 accuracy = 0.000000
class # 10 accuracy = 0.000000
class # 11 accuracy = 0.000000
class # 12 accuracy = 0.000000
class # 13 accuracy = 0.000000
class # 14 accuracy = 0.000000
class # 15 accuracy = 0.000000
class # 16 accuracy = 0.000000
class # 17 accuracy = 0.000000
class # 18 accuracy = 0.000000
class # 19 accuracy = 0.000000
class # 20 accuracy = 0.000000
class # 21 accuracy = 0.000000
class # 22 accuracy = 0.000000
class # 23 accuracy = 0.000000
class # 24 accuracy = 0.000000
class # 25 accuracy = 0.000000
class # 26 accuracy = 0.000000
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
2018-04-23 12:37:07.865742: step 120, loss = 1.54 (7.1 examples/sec; 0.281 sec/batch)
accuracy = 0.999881
mean IU = 0.076914
class # 0 accuracy = 0.999881
class # 1 accuracy = 0.000000
class # 2 accuracy = 0.000000
class # 3 accuracy = 0.000000
class # 4 accuracy = 0.000000
class # 5 accuracy = 0.000000
class # 6 accuracy = 0.000000
class # 7 accuracy = 0.000000
class # 8 accuracy = 0.000000
class # 9 accuracy = 0.000000
class # 10 accuracy = 0.000000
class # 11 accuracy = 0.000000
class # 12 accuracy = 0.000000
class # 13 accuracy = 0.000000
class # 14 accuracy = 0.000000
class # 15 accuracy = 0.000000
class # 16 accuracy = 0.000000
class # 17 accuracy = 0.000000
class # 18 accuracy = 0.000000
class # 19 accuracy = 0.000000
class # 20 accuracy = 0.000000
class # 21 accuracy = 0.000000
class # 22 accuracy = 0.000000
class # 23 accuracy = 0.000000
class # 24 accuracy = 0.000000
class # 25 accuracy = 0.000000
class # 26 accuracy = 0.000000
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
2018-04-23 12:37:11.694385: step 130, loss = 1.53 (7.3 examples/sec; 0.273 sec/batch)
accuracy = 1.000000
mean IU = 1.000000
class # 0 accuracy = 1.000000
class # 1 accuracy = 0.000000
class # 2 accuracy = 0.000000
class # 3 accuracy = 0.000000
class # 4 accuracy = 0.000000
class # 5 accuracy = 0.000000
class # 6 accuracy = 0.000000
class # 7 accuracy = 0.000000
class # 8 accuracy = 0.000000
class # 9 accuracy = 0.000000
class # 10 accuracy = 0.000000
class # 11 accuracy = 0.000000
class # 12 accuracy = 0.000000
class # 13 accuracy = 0.000000
class # 14 accuracy = 0.000000
class # 15 accuracy = 0.000000
class # 16 accuracy = 0.000000
class # 17 accuracy = 0.000000
class # 18 accuracy = 0.000000
class # 19 accuracy = 0.000000
class # 20 accuracy = 0.000000
class # 21 accuracy = 0.000000
class # 22 accuracy = 0.000000
class # 23 accuracy = 0.000000
class # 24 accuracy = 0.000000
class # 25 accuracy = 0.000000
class # 26 accuracy = 0.000000
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
2018-04-23 12:37:15.534847: step 140, loss = 1.52 (7.4 examples/sec; 0.272 sec/batch)
accuracy = 1.000000
mean IU = 1.000000
class # 0 accuracy = 1.000000
class # 1 accuracy = 0.000000
class # 2 accuracy = 0.000000
class # 3 accuracy = 0.000000
class # 4 accuracy = 0.000000
class # 5 accuracy = 0.000000
class # 6 accuracy = 0.000000
class # 7 accuracy = 0.000000
class # 8 accuracy = 0.000000
class # 9 accuracy = 0.000000
class # 10 accuracy = 0.000000
class # 11 accuracy = 0.000000
class # 12 accuracy = 0.000000
class # 13 accuracy = 0.000000
class # 14 accuracy = 0.000000
class # 15 accuracy = 0.000000
class # 16 accuracy = 0.000000
class # 17 accuracy = 0.000000
class # 18 accuracy = 0.000000
class # 19 accuracy = 0.000000
class # 20 accuracy = 0.000000
class # 21 accuracy = 0.000000
class # 22 accuracy = 0.000000
class # 23 accuracy = 0.000000
class # 24 accuracy = 0.000000
class # 25 accuracy = 0.000000
class # 26 accuracy = 0.000000
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
[ 2 360 480 3] [ 2 360 480 1]
2018-04-23 12:37:19.353283: step 150, loss = 1.51 (7.4 examples/sec; 0.272 sec/batch)
accuracy = 0.999844