README.md

---
license: apache-2.0
datasets:
- tedlium3
language:
- en
metrics:
- wer
---
### TedLium3 Zipformer

**`rnnt_type=regular`**

The WERs are

|                                    |     dev    |    test    | comment                                  |
|------------------------------------|------------|------------|------------------------------------------|
|          greedy search             | 6.74       | 6.16       | --epoch 50, --avg 22, --max-duration 500 |
|      beam search (beam size 4)     | 6.56       | 5.95       | --epoch 50, --avg 22, --max-duration 500 |
| modified beam search (beam size 4) | 6.54       | 6.00       | --epoch 50, --avg 22, --max-duration 500 |
| fast beam search (set as default)  | 6.91       | 6.28       | --epoch 50, --avg 22, --max-duration 500 |

The training command for reproducing is given below:

```
export CUDA_VISIBLE_DEVICES="0,1,2,3"

./zipformer/train.py \
  --use-fp16 true \
  --world-size 4 \
  --num-epochs 50 \
  --start-epoch 0 \
  --exp-dir zipformer/exp \
  --max-duration 1000
```

The tensorboard training log can be found at
https://tensorboard.dev/experiment/AKXbJha0S9aXyfmuvG4h5A/#scalars

The decoding command is:
```
epoch=50
avg=22

## greedy search
./zipformer/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir zipformer/exp \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 500

## beam search
./zipformer/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir zipformer/exp \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 500 \
  --decoding-method beam_search \
  --beam-size 4

## modified beam search
./zipformer/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir zipformer/exp \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 500 \
  --decoding-method modified_beam_search \
  --beam-size 4

## fast beam search
./zipformer/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./zipformer/exp \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 1500 \
  --decoding-method fast_beam_search \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8
```

**`rnnt_type=modified`**

Using the codes from this PR https://github.com/k2-fsa/icefall/pull/1125.

The WERs are

|                                    |     dev    |    test    | comment                                  |
|------------------------------------|------------|------------|------------------------------------------|
|          greedy search             | 6.32       | 5.83       | --epoch 50, --avg 22, --max-duration 500 |
| modified beam search (beam size 4) | 6.16       | 5.79       | --epoch 50, --avg 22, --max-duration 500 |
| fast beam search (set as default)  | 6.30       | 5.89       | --epoch 50, --avg 22, --max-duration 500 |

The training command for reproducing is given below:

```
export CUDA_VISIBLE_DEVICES="0,1,2,3"

./zipformer/train.py \
  --use-fp16 true \
  --world-size 4 \
  --num-epochs 50 \
  --start-epoch 0 \
  --exp-dir zipformer/exp \
  --max-duration 1000 \
  --rnnt-type modified
```

The tensorboard training log can be found at
https://tensorboard.dev/experiment/3d4bYmbJTGiWQQaW88CVEQ/#scalars

The decoding commands are same as above.