invalid batch

请问下，这个invalid batch 是怎么个逻辑计算的？代码没看明白、

raw_arr = np.column_stack((preds, labels))
raw_arr = sorted(raw_arr, key=lambda d: d[0])

auc = 0.
fp1, tp1, fp2, tp2 = 0., 0., 0., 0.
for record in raw_arr:
fp2 += 1 - record[1]
tp2 += record[1]
auc += (fp2 - fp1) * (tp2 + tp1)
fp1, tp1 = fp2, tp2

threshold = len(preds) - 1e-3
if tp2 > threshold or fp2 > threshold:
print('%s invalid batch' % self.name)
return

Start with the shown NumPy sorting and accumulation code, then trace where preds and labels are produced and how threshold is used. Determine what condition causes the invalid batch message and document the intended calculation and completion criteria.

Written by the indexing model from the issue text.