From 8672cad2cbe9b31d82e54223d0f4815ffe426cee Mon Sep 17 00:00:00 2001
From: Vincent Brouwers <vincent.brouwers@ing.com>
Date: Tue, 26 Sep 2023 16:16:43 +0200
Subject: [PATCH] Fix top_n_tokens returning non-log probs for some models
 (#1023)

# What does this PR do?

I made an embarrassing mistake where I accidentally passed normal
softmax probabilities into `batch_top_tokens` for `CausalLM` and
`Seq2SeqLM`.

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@Narsil
---
 server/text_generation_server/models/causal_lm.py  | 2 +-
 server/text_generation_server/models/seq2seq_lm.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/server/text_generation_server/models/causal_lm.py b/server/text_generation_server/models/causal_lm.py
index cec9ae55..696f0fb2 100644
--- a/server/text_generation_server/models/causal_lm.py
+++ b/server/text_generation_server/models/causal_lm.py
@@ -579,7 +579,7 @@ class CausalLM(Model):
         batch_top_token_ids, batch_top_token_logprobs = batch_top_tokens(
             batch.top_n_tokens,
             batch.top_n_tokens_tensor,
-            torch.softmax(logits[:, -1], -1),
+            torch.log_softmax(logits[:, -1], -1),
         )
 
         # Zipped iterator
diff --git a/server/text_generation_server/models/seq2seq_lm.py b/server/text_generation_server/models/seq2seq_lm.py
index 1a7911ac..34932c0b 100644
--- a/server/text_generation_server/models/seq2seq_lm.py
+++ b/server/text_generation_server/models/seq2seq_lm.py
@@ -642,7 +642,7 @@ class Seq2SeqLM(Model):
         batch_top_token_ids, batch_top_token_logprobs = batch_top_tokens(
             batch.top_n_tokens,
             batch.top_n_tokens_tensor,
-            torch.softmax(logits[:, -1], -1),
+            torch.log_softmax(logits[:, -1], -1),
         )
 
         # Finished requests