From c0277e3e11738049d023b9efddc1fda33ccc288f Mon Sep 17 00:00:00 2001
From: bobqianic <129547291+bobqianic@users.noreply.github.com>
Date: Tue, 6 Feb 2024 15:42:25 +0000
Subject: [PATCH] revert logsumexp implementation

---
 whisper.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/whisper.cpp b/whisper.cpp
index 54197e47f48..79e0e5eb092 100644
--- a/whisper.cpp
+++ b/whisper.cpp
@@ -4967,13 +4967,14 @@ static void whisper_process_logits(
             float timestamp_logprob = -INFINITY;
             {
                 float logsumexp = 0.0f;
+                const float logprob_max = *std::max_element(logprobs.begin() + vocab.token_beg, logprobs.end());
                 for (int i = vocab.token_beg; i < n_logits; ++i) {
                     if (logprobs[i] > -INFINITY) {
-                        logsumexp += expf(logprobs[i]);
+                        logsumexp += expf(logprobs[i] - logprob_max);
                     }
                 }
                 if (logsumexp > 0.0f) {
-                    timestamp_logprob = logf(logsumexp);
+                    timestamp_logprob = logf(logsumexp) + logprob_max;
                 }
             }