tensorflow/models · error · ValueError

Reference and translation files have different number of lin

Error message

Reference and translation files have different number of lines (%d VS %d). If training only a few steps (100-200), the translation may be empty.

What it means

Error "Reference and translation files have different number of lines (%d VS %d). If training only a few steps (100-200), the translation may be empty." thrown in tensorflow/models.

Source

Thrown at official/nlp/metrics/bleu.py:177

    else:
      precisions[i] = 0.0  # pyrefly: ignore[unsupported-operation]

  if max(precisions) > 0:
    p_log_sum = sum(math.log(p) for p in precisions if p)
    geo_mean = math.exp(p_log_sum / max_order)

  if use_bp:
    ratio = translation_length / reference_length
    bp = 0. if ratio < 1e-6 else math.exp(1 -
                                          1. / ratio) if ratio < 1.0 else 1.0
  bleu = geo_mean * bp
  return np.float32(bleu)


def bleu_on_list(ref_lines, hyp_lines, case_sensitive=False):
  """Compute BLEU for two list of strings (reference and hypothesis)."""
  if len(ref_lines) != len(hyp_lines):
    raise ValueError(
        "Reference and translation files have different number of "
        "lines (%d VS %d). If training only a few steps (100-200), the "
        "translation may be empty." % (len(ref_lines), len(hyp_lines)))
  if not case_sensitive:
    ref_lines = [x.lower() for x in ref_lines]
    hyp_lines = [x.lower() for x in hyp_lines]
  ref_tokens = [bleu_tokenize(x) for x in ref_lines]
  hyp_tokens = [bleu_tokenize(x) for x in hyp_lines]
  return compute_bleu(ref_tokens, hyp_tokens) * 100

View on GitHub (pinned to e006f5f0d5)

When it happens

Trigger: Thrown at official/nlp/metrics/bleu.py:177 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of tensorflow/models@e006f5f0d5 (2026-08-24). Data as JSON: /api/errors/abd0856912a8fdd3. Report an issue: GitHub.