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LAMA: LAnguage Model Analysis


LAMA is a probe for analyzing the factual and commonsense knowledge contained in pretrained language models.

The dataset for the LAMA probe is available at

LAMA contains a set of connectors to pretrained language models.
LAMA exposes a transparent and unique interface to use:

  • Transformer-XL (Dai et al., 2019)
  • BERT (Devlin et al., 2018)
  • ELMo (Peters et al., 2018)
  • GPT (Radford et al., 2018)
  • RoBERTa (Liu et al., 2019)

Actually, LAMA is also a beautiful animal.


The LAMA probe is described in the following papers:

  title={Language Models as Knowledge Bases?},
  author={F. Petroni, T. Rockt{\"{a}}schel, A. H. Miller, P. Lewis, A. Bakhtin, Y. Wu and S. Riedel},
  booktitle={In: Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing (EMNLP), 2019},

  title={How Context Affects Language Models' Factual Predictions},
  author={Fabio Petroni and Patrick Lewis and Aleksandra Piktus and Tim Rockt{\"a}schel and Yuxiang Wu and Alexander H. Miller and Sebastian Riedel},
  booktitle={Automated Knowledge Base Construction},

The LAMA probe

To reproduce our results:

1. Create conda environment and install requirements

(optional) It might be a good idea to use a separate conda environment. It can be created by running:

conda create -n lama37 -y python=3.7 && conda activate lama37
pip install -r requirements.txt

2. Download the data


3. Download the models

DISCLAIMER: ~55 GB on disk

Install spacy model

python3 -m spacy download en

Download the models

chmod +x

The script will create and populate a pre-trained_language_models folder. If you are interested in a particular model please edit the script.

4. Run the experiments

python scripts/

results will be logged in output/ and last_results.csv.

Other versions of LAMA


This repository also provides a script (scripts/ to create the data used in (Poerner et al., 2019).


This repository also gives the option to evalute how pretrained language models handle negated probes (Kassner et al., 2019), set the flag use_negated_probes in scripts/ Also, you should use this version of the LAMA probe

What else can you do with LAMA?

1. Encode a list of sentences

and use the vectors in your downstream task!

pip install -e git+
import argparse
from lama.build_encoded_dataset import encode, load_encoded_dataset

        "lm": "bert",
        "bert_model_name": "bert-large-cased",
        "bert_vocab_name": "vocab.txt",
        "batch_size": 32

args = argparse.Namespace(**PARAMETERS)

sentences = [
        ["The cat is on the table ."],  # single-sentence instance
        ["The dog is sleeping on the sofa .", "He makes happy noises ."],  # two-sentence

encoded_dataset = encode(args, sentences)
print("Embedding shape: %s" % str(encoded_dataset[0].embedding.shape))
print("Tokens: %r" % encoded_dataset[0].tokens)

# save on disk the encoded dataset"test.pkl")

# load from disk the encoded dataset
new_encoded_dataset = load_encoded_dataset("test.pkl")
print("Embedding shape: %s" % str(new_encoded_dataset[0].embedding.shape))
print("Tokens: %r" % new_encoded_dataset[0].tokens)

2. Fill a sentence with a gap.

You should use the symbol [MASK] to specify the gap. Only single-token gap supported - i.e., a single [MASK].

python lama/  \
--lm "bert"  \
--t "The cat is on the [MASK]."




Note that you could use this functionality to answer cloze-style questions, such as:

python lama/  \
--lm "bert"  \
--t "The theory of relativity was developed by [MASK] ."

Install LAMA with pip

Clone the repo

git clone && cd LAMA

Install as an editable package:

pip install --editable .

If you get an error in mac os x, please try running this instead

CFLAGS="-Wno-deprecated-declarations -std=c++11 -stdlib=libc++" pip install --editable .

Language Model(s) options

Option to indicate which language model(s) to use:

  • --language-models/--lm : comma separated list of language models (REQUIRED)


BERT pretrained models can be loaded both: (i) passing the name of the model and using huggingface cached versions or (ii) passing the folder containing the vocabulary and the PyTorch pretrained model (look at convert_tf_checkpoint_to_pytorch in here to convert the TensorFlow model to PyTorch).

  • --bert-model-dir/--bmd : directory that contains the BERT pre-trained model and the vocabulary
  • --bert-model-name/--bmn : name of the huggingface cached versions of the BERT pre-trained model (default = 'bert-base-cased')
  • --bert-vocab-name/--bvn : name of vocabulary used to pre-train the BERT model (default = 'vocab.txt')


  • --roberta-model-dir/--rmd : directory that contains the RoBERTa pre-trained model and the vocabulary (REQUIRED)
  • --roberta-model-name/--rmn : name of the RoBERTa pre-trained model (default = '')
  • --roberta-vocab-name/--rvn : name of vocabulary used to pre-train the RoBERTa model (default = 'dict.txt')


  • --elmo-model-dir/--emd : directory that contains the ELMo pre-trained model and the vocabulary (REQUIRED)
  • --elmo-model-name/--emn : name of the ELMo pre-trained model (default = 'elmo_2x4096_512_2048cnn_2xhighway')
  • --elmo-vocab-name/--evn : name of vocabulary used to pre-train the ELMo model (default = 'vocab-2016-09-10.txt')


  • --transformerxl-model-dir/--tmd : directory that contains the pre-trained model and the vocabulary (REQUIRED)
  • --transformerxl-model-name/--tmn : name of the pre-trained model (default = 'transfo-xl-wt103')


  • --gpt-model-dir/--gmd : directory that contains the gpt pre-trained model and the vocabulary (REQUIRED)
  • --gpt-model-name/--gmn : name of the gpt pre-trained model (default = 'openai-gpt')

Evaluate Language Model(s) Generation


  • --text/--t : text to compute the generation for
  • --i : interactive mode
    one of the two is required

example considering both BERT and ELMo:

python lama/ \
--lm "bert,elmo" \
--bmd "pre-trained_language_models/bert/cased_L-24_H-1024_A-16/" \
--emd "pre-trained_language_models/elmo/original/" \
--t "The cat is on the [MASK]."

example considering only BERT with the default pre-trained model, in an interactive fashion:

python lamas/  \
--lm "bert"  \

Get Contextual Embeddings

python lama/ \
--lm "bert,elmo" \
--bmn bert-base-cased \
--emd "pre-trained_language_models/elmo/original/"

Unified vocabulary

The intersection of the vocabularies for all considered models


If the module cannot be found, preface the python command with PYTHONPATH=.

If the experiments fail on GPU memory allocation, try reducing batch size.


Other References

  • (Kassner et al., 2019) Nora Kassner, Hinrich Schütze. Negated LAMA: Birds cannot fly. arXiv preprint arXiv:1911.03343, 2019.

  • (Poerner et al., 2019) Nina Poerner, Ulli Waltinger, and Hinrich Schütze. BERT is Not a Knowledge Base (Yet): Factual Knowledge vs. Name-Based Reasoning in Unsupervised QA. arXiv preprint arXiv:1911.03681, 2019.

  • (Dai et al., 2019) Zihang Dai, Zhilin Yang, Yiming Yang, Jaime G. Carbonell, Quoc V. Le, and Ruslan Salakhutdi. Transformer-xl: Attentive language models beyond a fixed-length context. CoRR, abs/1901.02860.

  • (Peters et al., 2018) Matthew E. Peters, Mark Neumann, Mohit Iyyer, Matt Gardner, Christopher Clark, Kenton Lee, and Luke Zettlemoyer. 2018. Deep contextualized word representations. NAACL-HLT 2018

  • (Devlin et al., 2018) Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. 2018. BERT: pre-training of deep bidirectional transformers for language understanding. CoRR, abs/1810.04805.

  • (Radford et al., 2018) Alec Radford, Karthik Narasimhan, Tim Salimans, and Ilya Sutskever. 2018. Improving language understanding by generative pre-training.

  • (Liu et al., 2019) Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, Veselin Stoyanov. 2019. RoBERTa: A Robustly Optimized BERT Pretraining Approach. arXiv preprint arXiv:1907.11692.


LAMA is licensed under the CC-BY-NC 4.0 license. The text of the license can be found here.


LAnguage Model Analysis



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