Transformer¶
We offer a variety of agent implementations whose core model is the transformer, a self-attention based encoding mechanism first described in Vaswani et al 2017.
Agent Variations¶
transformer/biencoder
- A retrieval-based agent that encodes a context sequence and a candidate sequence with separate BERT-based Transformers. A candidate is chosen via the highest dot-product score between the context and candidate encodings. See Humeau et al 2019 for more details.transformer/classifier
- A classifier agent with a Transformer as the model.transformer/crossencoder
- A retrieval-based agent that jointly encodes a context and candidate sequence in a single BERT-based Transformer, with a final linear layer used to compute a score. A candidate is chosen via the highest scoring encoding. See Humeau et al 2019 for more details.transformer/generator
- A generative-based agent that performs seq2seq encoding/decoding with transformer encoders/decoders.transformer/polyencoder
- A retrieval-based agent that, similar to the bi-encoder agent, encodes context and candidate sequences with separate BERT-based Transformers. However, to compute a final score, the agent performs an additional layer of attention using global context vectors before computing the final dot product, thus incorporating the candidate encoding into the context encoding prior to producing a dot-product score. See Humeau et al 2019 for more details.transformer/ranker
- A retrieval-based agent that encodes a context sequence and a candidate sequence with separate Transformers, before computing a dot-product to obtain a score for a candidate encoding.
TransformerClassifierAgent Options¶
optional arguments
Argument |
Description |
---|---|
|
Share word embeddings table for candidate and contextin the memory network |
|
Load model from base transformer ranking model (used for pretraining) |
TorchRankerAgent
Argument |
Description |
---|---|
|
The source of candidates during training (see TorchRankerAgent._build_candidates() for details). |
|
The source of candidates during evaluation (defaults to the samevalue as –candidates if no flag is given) |
|
The source of candidates during interactive mode. Since in interactive mode, batchsize == 1, we cannot use batch candidates. |
|
Block repeating previous utterances. Helpful for many models that score repeats highly, so switched on by default. |
|
A text file of fixed candidates to use for all examples, one candidate per line |
|
One of “reuse”, “replace”, or a path to a file with vectors corresponding to the candidates at –fixed-candidates-path. The default path is a /path/to/model-file.<cands_name>, where <cands_name> is the name of the file (not the full path) passed by the flag –fixed-candidates-path. By default, this file is created once and reused. To replace it, use the “replace” option. |
|
Cache and save the encoding of the candidate vecs. This might be used when interacting with the model in real time or evaluating on fixed candidate set when the encoding of the candidates is independent of the input. |
|
Initialize model with weights from this file. |
|
Get predictions and calculate mean rank during the train step. Turning this on may slow down training. |
|
Limit to the number of predictions in output.text_candidates |
|
Ignore examples for which the label is not present in the label candidates. Default behavior results in RuntimeError. |
|
Ranking returns the top k results of k > 0, otherwise sorts every single candidate according to the ranking. |
|
Final response output algorithm |
|
K used in Top K sampling inference, when selected |
|
Return sorted candidate scores from eval_step |
Transformer Arguments
Argument |
Description |
---|---|
|
Size of all embedding layers. Must be a multiple of –n-heads. |
|
Number of transformer layers. |
|
Hidden size of the FFN layers |
|
Dropout used around embeddings and before layer layer normalizations. This is used in Vaswani 2017 and works well on large datasets. |
|
Dropout used after attention softmax. This is not used in Vaswani 2017. |
|
Dropout used after the ReLU in the FFN. Not used in Vaswani 2017, but used in Tensor2Tensor. |
|
Number of multihead attention heads |
|
If off, sinusoidal embeddings are used. If on, position embeddings are learned from scratch. |
|
Default: |
|
The number of segments that support the model. If zero no segment and no langs_embedding. |
|
Chooses locations of layer norms, etc. prelayernorm is used to match some fairseq models |
|
Nonlinear activation to use. AIAYN uses relu, but more recent papers prefer gelu. |
|
Scale the output of every transformer by this quantity. |
|
This will overidde the n-layers for asymmetrical transformers |
|
This will overidde the n-layers for asymmetrical transformers |
|
Shard the layers across multiple GPUs. |
|
Recompute activations on backward pass to conserve memory. |
|
Use memories: must implement the function |
|
Wrap memory encoder with MLP |
|
Similarity for basic attention mechanism when using transformer to encode memories |
|
Default: |
|
Default: |
|
Learn embeddings |
|
Type of reduction at the end of transformer |
TorchAgent Arguments
Argument |
Description |
---|---|
|
Whether in full interactive mode or not, which means generating text or retrieving from a full set of candidates, which is necessary to actually do full dialogue. However, during training or quick validation (e.g. PPL for generation or ranking a few candidates for ranking models) you might want these set to off. Typically, scripts can set their preferred default behavior at the start, e.g. eval scripts. |
|
Choose between different strategies for initializing word embeddings. Default is random, but can also preinitialize from Glove or Fasttext. Preinitialized embeddings can also be fixed so they are not updated during training. |
|
If pretrained embeddings have a different dimensionality than your embedding size, strategy for projecting to the correct size. If the dimensions are the same, this is ignored unless you append “-force” to your choice. |
|
Use fp16 computations. |
|
Implementation of FP16 to use |
|
Whether the model should parse candidates for ranking. |
|
Truncate input lengths to increase speed / use less memory. |
|
Text input truncation length: if not specified, this will default to |
|
Label truncation length: if not specified, this will default to |
|
Reverse the history |
|
Number of past dialog utterances to remember. |
|
Add person tokens to history. adds p1 in front of input text and p2 in front of past labels when available or past utterances generated by the model. these are added to the dictionary during initialization. |
|
Split the dialogue history on newlines and save in separate vectors |
|
Join history lines with this token, defaults to newline |
|
Comma separated list of special tokens. In case of ambiguous parses from special tokens, the ordering provided in this arg sets precedence. |
|
Which GPU to use |
|
Disable GPUs even if available. otherwise, will use GPUs if available on the device. |
Optimizer Arguments
Argument |
Description |
---|---|
|
Optimizer choice. Possible values: adadelta, adagrad, adam, adamw, sparseadam, adamax, asgd, sgd, radam, rprop, rmsprop, optimizer, nadam, lbfgs, mem_eff_adam, adafactor. |
|
Learning rate |
|
Gradient clipping using l2 norm |
|
Epsilon values for adafactor optimizer: regularization constants for square gradient and parameter scale respectively |
|
If applicable, momentum value for optimizer. |
|
If applicable, whether to use nesterov momentum. |
|
If applicable, nu value(s) for optimizer. can use a single value like 0.7 or a comma-separated tuple like 0.7,1.0 |
|
If applicable, beta value(s) for optimizer. can use a single value like 0.9 or a comma-separated tuple like 0.9,0.999 |
|
Weight decay on the weights. |
BPEHelper Arguments
Argument |
Description |
---|---|
|
Path to pre-trained tokenizer vocab |
|
Path to pre-trained tokenizer merge |
|
Use BPE dropout during training. |
Learning Rate Scheduler
Argument |
Description |
---|---|
|
Learning rate scheduler. |
|
LR scheduler patience. In number of validation runs. If using fixed scheduler, LR is decayed every |
|
Decay factor for LR scheduler, or how much LR is multiplied by when it is lowered. |
|
Constant used only to find the lr multiplier for the invsqrt scheduler. Must be set for –lr-scheduler invsqrt |
Torch Classifier Arguments
Argument |
Description |
---|---|
|
The name of the classes. |
|
Weight of each of the classes for the softmax |
|
During evaluation, threshold for choosing ref class; only applies to binary classification |
|
Print probability of chosen class during interactive mode |
|
Uses nn.DataParallel for multi GPU |
|
Loads the list of classes from a file |
|
Ignore labels provided to model |
|
Freeze the encoder and update the classifier head only |
TransformerGeneratorAgent Options¶
optional arguments
Argument |
Description |
---|---|
|
Set to use CUDA kernel for beam search ngram blocking |
|
Return the topk logits in the act message, if verbose mode is set. |
Transformer Arguments
Argument |
Description |
---|---|
|
Size of all embedding layers. Must be a multiple of –n-heads. |
|
Number of transformer layers. |
|
Hidden size of the FFN layers |
|
Dropout used around embeddings and before layer layer normalizations. This is used in Vaswani 2017 and works well on large datasets. |
|
Dropout used after attention softmax. This is not used in Vaswani 2017. |
|
Dropout used after the ReLU in the FFN. Not used in Vaswani 2017, but used in Tensor2Tensor. |
|
Number of multihead attention heads |
|
If off, sinusoidal embeddings are used. If on, position embeddings are learned from scratch. |
|
Default: |
|
The number of segments that support the model. If zero no segment and no langs_embedding. |
|
Chooses locations of layer norms, etc. prelayernorm is used to match some fairseq models |
|
Nonlinear activation to use. AIAYN uses relu, but more recent papers prefer gelu. |
|
Scale the output of every transformer by this quantity. |
|
Share word embeddings table for candidate and contextin the memory network |
|
This will overidde the n-layers for asymmetrical transformers |
|
This will overidde the n-layers for asymmetrical transformers |
|
Shard the layers across multiple GPUs. |
|
Recompute activations on backward pass to conserve memory. |
Torch Generator Agent
Argument |
Description |
---|---|
|
Beam size, if 1 then greedy search |
|
Minimum length of prediction to be generated by the beam search |
|
Size n-grams to block in beam search from the context. val <= 0 implies no blocking |
|
Size n-grams to block in beam search. val <= 0 implies no blocking |
|
Block n-grams from the full history context. Specify False to block up to m tokens in the past, where m is truncation parameter for agent |
|
Applies a length penalty. Set to 0 for no penalty. |
|
Generation algorithm |
|
K used in Top K sampling |
|
P used in nucleus sampling |
|
Used in delayedbeam search |
|
Decay factor in factual nucleus sampling |
|
Lower bound in factual nucleus sampling |
|
Whether to reset p value in factual nucleus at full stops |
|
Load a text file of hard blocks for beam search to never say. |
|
Temperature to add during decoding |
|
If true, compute tokenized bleu scores |
TorchAgent Arguments
Argument |
Description |
---|---|
|
Whether in full interactive mode or not, which means generating text or retrieving from a full set of candidates, which is necessary to actually do full dialogue. However, during training or quick validation (e.g. PPL for generation or ranking a few candidates for ranking models) you might want these set to off. Typically, scripts can set their preferred default behavior at the start, e.g. eval scripts. |
|
Choose between different strategies for initializing word embeddings. Default is random, but can also preinitialize from Glove or Fasttext. Preinitialized embeddings can also be fixed so they are not updated during training. |
|
If pretrained embeddings have a different dimensionality than your embedding size, strategy for projecting to the correct size. If the dimensions are the same, this is ignored unless you append “-force” to your choice. |
|
Use fp16 computations. |
|
Implementation of FP16 to use |
|
Whether the model should parse candidates for ranking. |
|
Truncate input lengths to increase speed / use less memory. |
|
Text input truncation length: if not specified, this will default to |
|
Label truncation length: if not specified, this will default to |
|
Reverse the history |
|
Number of past dialog utterances to remember. |
|
Add person tokens to history. adds p1 in front of input text and p2 in front of past labels when available or past utterances generated by the model. these are added to the dictionary during initialization. |
|
Split the dialogue history on newlines and save in separate vectors |
|
Join history lines with this token, defaults to newline |
|
Comma separated list of special tokens. In case of ambiguous parses from special tokens, the ordering provided in this arg sets precedence. |
|
Which GPU to use |
|
Disable GPUs even if available. otherwise, will use GPUs if available on the device. |
Optimizer Arguments
Argument |
Description |
---|---|
|
Optimizer choice. Possible values: adadelta, adagrad, adam, adamw, sparseadam, adamax, asgd, sgd, radam, rprop, rmsprop, optimizer, nadam, lbfgs, mem_eff_adam, adafactor. |
|
Learning rate |
|
Gradient clipping using l2 norm |
|
Epsilon values for adafactor optimizer: regularization constants for square gradient and parameter scale respectively |
|
If applicable, momentum value for optimizer. |
|
If applicable, whether to use nesterov momentum. |
|
If applicable, nu value(s) for optimizer. can use a single value like 0.7 or a comma-separated tuple like 0.7,1.0 |
|
If applicable, beta value(s) for optimizer. can use a single value like 0.9 or a comma-separated tuple like 0.9,0.999 |
|
Weight decay on the weights. |
BPEHelper Arguments
Argument |
Description |
---|---|
|
Path to pre-trained tokenizer vocab |
|
Path to pre-trained tokenizer merge |
|
Use BPE dropout during training. |
Learning Rate Scheduler
Argument |
Description |
---|---|
|
Learning rate scheduler. |
|
LR scheduler patience. In number of validation runs. If using fixed scheduler, LR is decayed every |
|
Decay factor for LR scheduler, or how much LR is multiplied by when it is lowered. |
|
Constant used only to find the lr multiplier for the invsqrt scheduler. Must be set for –lr-scheduler invsqrt |
TransformerRankerAgent Options¶
optional arguments
Argument |
Description |
---|---|
|
Share word embeddings table for candidate and contextin the memory network |
TorchAgent Arguments
Argument |
Description |
---|---|
|
Whether in full interactive mode or not, which means generating text or retrieving from a full set of candidates, which is necessary to actually do full dialogue. However, during training or quick validation (e.g. PPL for generation or ranking a few candidates for ranking models) you might want these set to off. Typically, scripts can set their preferred default behavior at the start, e.g. eval scripts. |
|
Choose between different strategies for initializing word embeddings. Default is random, but can also preinitialize from Glove or Fasttext. Preinitialized embeddings can also be fixed so they are not updated during training. |
|
If pretrained embeddings have a different dimensionality than your embedding size, strategy for projecting to the correct size. If the dimensions are the same, this is ignored unless you append “-force” to your choice. |
|
Use fp16 computations. |
|
Implementation of FP16 to use |
|
Whether the model should parse candidates for ranking. |
|
Truncate input lengths to increase speed / use less memory. |
|
Text input truncation length: if not specified, this will default to |
|
Label truncation length: if not specified, this will default to |
|
Reverse the history |
|
Number of past dialog utterances to remember. |
|
Add person tokens to history. adds p1 in front of input text and p2 in front of past labels when available or past utterances generated by the model. these are added to the dictionary during initialization. |
|
Split the dialogue history on newlines and save in separate vectors |
|
Join history lines with this token, defaults to newline |
|
Comma separated list of special tokens. In case of ambiguous parses from special tokens, the ordering provided in this arg sets precedence. |
|
Which GPU to use |
|
Disable GPUs even if available. otherwise, will use GPUs if available on the device. |
Optimizer Arguments
Argument |
Description |
---|---|
|
Optimizer choice. Possible values: adadelta, adagrad, adam, adamw, sparseadam, adamax, asgd, sgd, radam, rprop, rmsprop, optimizer, nadam, lbfgs, mem_eff_adam, adafactor. |
|
Learning rate |
|
Gradient clipping using l2 norm |
|
Epsilon values for adafactor optimizer: regularization constants for square gradient and parameter scale respectively |
|
If applicable, momentum value for optimizer. |
|
If applicable, whether to use nesterov momentum. |
|
If applicable, nu value(s) for optimizer. can use a single value like 0.7 or a comma-separated tuple like 0.7,1.0 |
|
If applicable, beta value(s) for optimizer. can use a single value like 0.9 or a comma-separated tuple like 0.9,0.999 |
|
Weight decay on the weights. |
Learning Rate Scheduler
Argument |
Description |
---|---|
|
Learning rate scheduler. |
|
LR scheduler patience. In number of validation runs. If using fixed scheduler, LR is decayed every |
|
Decay factor for LR scheduler, or how much LR is multiplied by when it is lowered. |
|
Constant used only to find the lr multiplier for the invsqrt scheduler. Must be set for –lr-scheduler invsqrt |
TorchRankerAgent
Argument |
Description |
---|---|
|
The source of candidates during training (see TorchRankerAgent._build_candidates() for details). |
|
The source of candidates during evaluation (defaults to the samevalue as –candidates if no flag is given) |
|
The source of candidates during interactive mode. Since in interactive mode, batchsize == 1, we cannot use batch candidates. |
|
Block repeating previous utterances. Helpful for many models that score repeats highly, so switched on by default. |
|
A text file of fixed candidates to use for all examples, one candidate per line |
|
One of “reuse”, “replace”, or a path to a file with vectors corresponding to the candidates at –fixed-candidates-path. The default path is a /path/to/model-file.<cands_name>, where <cands_name> is the name of the file (not the full path) passed by the flag –fixed-candidates-path. By default, this file is created once and reused. To replace it, use the “replace” option. |
|
Cache and save the encoding of the candidate vecs. This might be used when interacting with the model in real time or evaluating on fixed candidate set when the encoding of the candidates is independent of the input. |
|
Initialize model with weights from this file. |
|
Get predictions and calculate mean rank during the train step. Turning this on may slow down training. |
|
Limit to the number of predictions in output.text_candidates |
|
Ignore examples for which the label is not present in the label candidates. Default behavior results in RuntimeError. |
|
Ranking returns the top k results of k > 0, otherwise sorts every single candidate according to the ranking. |
|
Final response output algorithm |
|
K used in Top K sampling inference, when selected |
|
Return sorted candidate scores from eval_step |
Transformer Arguments
Argument |
Description |
---|---|
|
Size of all embedding layers. Must be a multiple of –n-heads. |
|
Number of transformer layers. |
|
Hidden size of the FFN layers |
|
Dropout used around embeddings and before layer layer normalizations. This is used in Vaswani 2017 and works well on large datasets. |
|
Dropout used after attention softmax. This is not used in Vaswani 2017. |
|
Dropout used after the ReLU in the FFN. Not used in Vaswani 2017, but used in Tensor2Tensor. |
|
Number of multihead attention heads |
|
If off, sinusoidal embeddings are used. If on, position embeddings are learned from scratch. |
|
Default: |
|
The number of segments that support the model. If zero no segment and no langs_embedding. |
|
Chooses locations of layer norms, etc. prelayernorm is used to match some fairseq models |
|
Nonlinear activation to use. AIAYN uses relu, but more recent papers prefer gelu. |
|
Scale the output of every transformer by this quantity. |
|
This will overidde the n-layers for asymmetrical transformers |
|
This will overidde the n-layers for asymmetrical transformers |
|
Shard the layers across multiple GPUs. |
|
Recompute activations on backward pass to conserve memory. |
|
Use memories: must implement the function |
|
Wrap memory encoder with MLP |
|
Similarity for basic attention mechanism when using transformer to encode memories |
|
Default: |
|
Default: |
|
Learn embeddings |
|
Use model in data parallel, requires multiple gpus |
|
Type of reduction at the end of transformer |
BPEHelper Arguments
Argument |
Description |
---|---|
|
Path to pre-trained tokenizer vocab |
|
Path to pre-trained tokenizer merge |
|
Use BPE dropout during training. |