From 1e3d264b4699ef8a6524934331f0b0efcee75f92 Mon Sep 17 00:00:00 2001
From: qweasdzxcvde <35418904+qweasdzxcvde@users.noreply.github.com>
Date: Mon, 8 Sep 2025 14:29:57 +0800
Subject: [PATCH] add tot_score inf mask to make training stable

I find there are some inf in tot_score, it makes model cannot converge, add inf mask can make training more stable.
---
 icefall/mmi.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/icefall/mmi.py b/icefall/mmi.py
index b7777b434..2de8f1aae 100644
--- a/icefall/mmi.py
+++ b/icefall/mmi.py
@@ -124,6 +124,7 @@ def _compute_mmi_loss_exact_non_optimized(
     den_tot_scores = den_lats.get_tot_scores(log_semiring=True, use_double_scores=True)
 
     tot_scores = num_tot_scores - den_scale * den_tot_scores
+    tot_scores = tot_scores.masked_fill(torch.isinf(tot_scores), 0.0)
 
     loss = -1 * tot_scores.sum()
     return loss