When I trained the CUB datebase,I got this result.Why top-1 and top_5 is 0?

[ltc576935585]

Epoch: [0][20/300] Time 0.925 (0.968) ETA 00:28:44(00:04:50) Loss 5.3001 (5.6576) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][40/300] Time 0.912 (0.943) ETA 00:27:40(00:04:42) Loss 5.4433 (5.5504) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][60/300] Time 0.920 (0.937) ETA 00:27:11(00:04:41) Loss 5.4316 (5.4998) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][80/300] Time 0.923 (0.937) ETA 00:26:52(00:04:41) Loss 5.6090 (5.4800) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][100/300] Time 0.941 (0.934) ETA 00:26:28(00:04:40) Loss 5.3967 (5.4582) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][120/300] Time 0.938 (0.934) ETA 00:26:09(00:04:40) Loss 5.3338 (5.4500) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][140/300] Time 0.943 (0.938) ETA 00:25:58(00:04:41) Loss 5.3689 (5.4394) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][160/300] Time 1.014 (0.941) ETA 00:25:43(00:04:42) Loss 5.4100 (5.4387) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][180/300] Time 0.942 (0.942) ETA 00:25:26(00:04:42) Loss 5.3895 (5.4408) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][200/300] Time 0.939 (0.942) ETA 00:25:08(00:04:42) Loss 5.9786 (5.4488) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][220/300] Time 0.942 (0.942) ETA 00:24:49(00:04:42) Loss 5.5643 (5.4577) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][240/300] Time 0.947 (0.943) ETA 00:24:32(00:04:42) Loss 5.5316 (5.4707) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][260/300] Time 0.948 (0.943) ETA 00:24:13(00:04:43) Loss 5.6451 (5.4792) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][280/300] Time 0.945 (0.944) ETA 00:23:55(00:04:43) Loss 5.8763 (5.4896) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) Epoch: [0][0/300] Time 0.679 (0.943) ETA 00:23:35(00:04:42) Loss 5.6554 (5.4943) Prec@1 0.000 (0.000) Prec@5 0.000 (0.000) 0,5.4943,0.000,0.000