epoch: 1 valid swapped pairs: 1095/4950 ndcg: 0.8722
epoch: 2 valid swapped pairs: 787/4950 ndcg: 0.9366
epoch: 3 valid swapped pairs: 548/4950 ndcg: 0.9701
epoch: 4 valid swapped pairs: 385/4950 ndcg: 0.9841
epoch: 5 valid swapped pairs: 275/4950 ndcg: 0.9908
epoch: 6 valid swapped pairs: 224/4950 ndcg: 0.9937
epoch: 7 valid swapped pairs: 182/4950 ndcg: 0.9952
epoch: 8 valid swapped pairs: 146/4950 ndcg: 0.9966
epoch: 9 valid swapped pairs: 139/4950 ndcg: 0.9965
epoch: 10 valid swapped pairs: 113/4950 ndcg: 0.9972