Fix bug in whisper transformer (#2681)

* Fix bug in whisper transformer
- due to num_threads going to zero
in single threaded case

* Apply rustfmt.

---------

Co-authored-by: Laurent <laurent.mazare@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/candle-transformers/src/models/whisper/audio.rs b/candle-transformers/src/models/whisper/audio.rs
index 35f9f3df..8490533c 100644
--- a/candle-transformers/src/models/whisper/audio.rs
+++ b/candle-transformers/src/models/whisper/audio.rs
@@ -204,6 +204,7 @@ pub fn log_mel_spectrogram_<T: Float>(
 
     // ensure that the number of threads is even and less than 12
     let n_threads = std::cmp::min(get_num_threads() - get_num_threads() % 2, 12);
+    let n_threads = std::cmp::max(n_threads, 2);
 
     let hann = Arc::new(hann);
     let samples = Arc::new(samples);