NMT Attention Alignment Visualizations

An attention alignment visualization tool for command line and web.

A part of the web version was borrowed from Nematus utils

Usage

• Train a neural MT system (like Neural Monkey or Nematus)
• Translate text and get word or subword level alignments
• Visualize the alignments
  • in the command line standard output
  • in a web browser (PHP required)

Requirements

• Python 2 or 3

  • NLTK (for BLEU calculation)

• PHP 5.4 or newer (for web visualization)

How to get alignment files from NMT systems

• Nematus

  • Run nematus/translate.py with the --output_alignment or -a parameter

• Neural Monkey

  • In the training.ini file add

   [alignment_saver]
   class=runners.word_alignment_runner.WordAlignmentRunner
   output_series="ali"
   encoder=<encoder>
   decoder=<decoder>

  and add alignment_saver to the runners in main

   runners=[<runner_greedy>, <alignment_saver>]

  • In the translation.ini file in eval_data add

   s_ali_out="out.alignment"

• Marian

  • In the config.yml file add

   no-debpe: true
   return-alignment: false
   return-soft-alignment: true

  • Or run amun with the parameters --no-debpe --return-soft-alignment

• OpenNMT Run translate.lua to translate with the -save_attention parameter to save attentions to a file

• Sockeye Run sockeye.translate to translate with the --output-type parameter set to translation_with_alignment_matrix to save attentions to a file

• Other The easiest format to use (and convert to) is the one used by Nematus.

  For each sentence the first row should be <sentence id> ||| <target words> ||| <score> ||| <source words> ||| <number of source words> <number of target words>

  After that follow <number of target words> + 1 (for <EOS> token) rows with <number of source words> + 1 (for <EOS> token) columns with attention weights separated by spaces.

  After each sentence there should be an empty line.

  Note that the values of <sentence id>, <score>, <number of source words> and <number of target words> are actually ignored when creating visualizations, so they may as well all be 0.

  An example:

   0 ||| Obama welcomes Netanyahu ||| 0 ||| Obama empfängt Net@@ any@@ ah@@ u ||| 7 4
   0.723834 0.0471278 0.126415 0.000413103 0.000774298 0.000715227 0.10072 
   0.00572539 0.743366 0.0342341 0.000315413 0.00550132 0.00150629 0.209351 
   0.0122618 0.0073559 0.909192 0.000606444 0.00614908 0.00256837 0.0618667 
   0.00110054 0.0214063 0.0759918 0.000446028 0.104856 0.0435644 0.752634 
   

Publications

If you use this tool, please cite the following paper:

Matīss Rikters, Mark Fishel, Ondřej Bojar (2017). "Visualizing Neural Machine Translation Attention and Confidence." In The Prague Bulletin of Mathematical Linguistics volume 109 (2017).

@inproceedings{Rikters-EtAl2017PBML,
	author = {Rikters, Matīss and Fishel, Mark and Bojar, Ond\v{r}ej},
	journal={The Prague Bulletin of Mathematical Linguistics},
	volume={109},
	pages = {1--12},
	title = {{Visualizing Neural Machine Translation Attention and Confidence}},
	address={Lisbon, Portugal},
	year = {2017}
}

Examples

• in the command line as shaded blocks. Example with Neural Monkey alignments (separate source and target subword unit files are required)

  python process_alignments.py \
  -i test_data/neuralmonkey/alignments.npy  \
  -o color \
  -s test_data/neuralmonkey/src.en.bpe \
  -t test_data/neuralmonkey/out.lv.bpe \
  -f NeuralMonkey

• the same with Nematus alignments (source and target subword units are in the same file)

  python process_alignments.py \
  -i test_data/nematus/alignments.txt \
  -o color \
  -f Nematus

• in a text file as Unicode block elements

  python process_alignments.py \
  -i test_data/neuralmonkey/alignments.npy  \
  -o block \
  -s test_data/neuralmonkey/src.en.bpe \
  -t test_data/neuralmonkey/out.lv.bpe \
  -f NeuralMonkey

  or

  python process_alignments.py \
  -i test_data/neuralmonkey/alignments.npy  \
  -o block2 \
  -s test_data/neuralmonkey/src.en.bpe \
  -t test_data/neuralmonkey/out.lv.bpe \
  -f NeuralMonkey
  

• in the browser as links between words (demo here)

  python process_alignments.py \
  -i test_data/marian/marian.out.lv \
  -s test_data/marian/marian.src.en \
  -o web \
  -f Marian

Parameters for process_alignments.py

Option	Description	Required	Possible Values	Default Value
-f	NMT framework where the alignments are from	No	'NeuralMonkey', 'Nematus', 'Marian', 'OpenNMT', 'Sockeye'	'NeuralMonkey'
-i	input alignment file	Only if no configuration file is provided	Path to file
-s	source sentence subword units	For Neural Monkey or Marian	Path to file
-t	target sentence subword units	For Neural Monkey	Path to file
-o	output type	No	'web', 'color', 'block', 'block2', 'compare'	'web'
-r	reference file for calculating BLEU score	No	Path to file
-n	Number of a specific sentence	No	Integer	-1 (show all)
-c	configuration file	No	Path to file
-v	NMT framework where the 2nd alignments are from	For output type'compare'	'NeuralMonkey', 'Nematus', 'Marian', 'OpenNMT', 'Sockeye'	'NeuralMonkey'
-w	input file for the 2nd alignments	For output type'compare'	Path to file
-x	2nd source sentence subword unit file	For output type'compare' and Neural Monkey or Marian	Path to file
-y	2nd target sentence subword unit file	For output type'compare' and Neural Monkey	Path to file

Configuration file

The parameters can be provided via configuration .ini file to have a smaller mess in the command line when calling the script.

Block	Option	Description
AlignmentsOne	From	NMT framework where the alignments are from
AlignmentsOne	InputFile	input alignment file
AlignmentsOne	SourceFile	source sentence subword units
AlignmentsOne	TargetFile	target sentence subword units
AlignmentsOne	ReferenceFile	reference file for calculating BLEU score
Options	OutputType	output type
Options	Number	Number of a specific sentence
AlignmentsTwo	From	NMT framework where the 2nd alignments are from
AlignmentsTwo	InputFile	input file for the 2nd alignments
AlignmentsTwo	SourceFile	2nd source sentence subword unit file
AlignmentsTwo	TargetFile	2nd target sentence subword unit file

For example, create a config.ini file:

[AlignmentsOne]
InputFile: ./test_data/neuralmonkey/alignments.npy
SourceFile: ./test_data/neuralmonkey/src.en.bpe
TargetFile: ./test_data/neuralmonkey/out.lv.bpe
From: NeuralMonkey

[Options]
OutputType: color

And run:

python process_alignments.py -c config.ini

Screenshots

Color, Block, Block2

Web

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