llama : add classifier-free guidance (#2135)

* Initial implementation

* Remove debug print

* Restore signature of llama_init_from_gpt_params

* Free guidance context

* Make freeing of guidance_ctx conditional

* Make Classifier-Free Guidance a sampling function

* Correct typo. CFG already means context-free grammar.

* Record sampling time in llama_sample_classifier_free_guidance

* Shift all values by the max value before applying logsoftmax

* Fix styling based on review
This commit is contained in:
Bach Le 2023-07-12 00:18:43 +08:00 committed by GitHub
parent 3ec7e596b2
commit c9c74b4e3f
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 188 additions and 5 deletions

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@ -236,6 +236,24 @@ bool gpt_params_parse(int argc, char ** argv, gpt_params & params) {
break;
}
params.mirostat_tau = std::stof(argv[i]);
} else if (arg == "--cfg-negative-prompt") {
if (++i >= argc) {
invalid_param = true;
break;
}
params.cfg_negative_prompt = argv[i];
} else if (arg == "--cfg-scale") {
if (++i >= argc) {
invalid_param = true;
break;
}
params.cfg_scale = std::stof(argv[i]);
} else if (arg == "--cfg-smooth-factor") {
if (++i >= argc) {
invalid_param = true;
break;
}
params.cfg_smooth_factor = std::stof(argv[i]);
} else if (arg == "-b" || arg == "--batch-size") {
if (++i >= argc) {
invalid_param = true;
@ -469,6 +487,10 @@ void gpt_print_usage(int /*argc*/, char ** argv, const gpt_params & params) {
fprintf(stderr, " modifies the likelihood of token appearing in the completion,\n");
fprintf(stderr, " i.e. `--logit-bias 15043+1` to increase likelihood of token ' Hello',\n");
fprintf(stderr, " or `--logit-bias 15043-1` to decrease likelihood of token ' Hello'\n");
fprintf(stderr, " --cfg-negative-prompt PROMPT \n");
fprintf(stderr, " negative prompt to use for guidance. (default: empty)\n");
fprintf(stderr, " --cfg-scale N strength of guidance (default: %f, 1.0 = disable)\n", params.cfg_scale);
fprintf(stderr, " --cfg-smooth-factor N smooth factor between old and new logits (default: %f, 1.0 = no smoothing)\n", params.cfg_smooth_factor);
fprintf(stderr, " -c N, --ctx-size N size of the prompt context (default: %d)\n", params.n_ctx);
fprintf(stderr, " --ignore-eos ignore end of stream token and continue generating (implies --logit-bias 2-inf)\n");
fprintf(stderr, " --no-penalize-nl do not penalize newline token\n");
@ -535,7 +557,7 @@ std::vector<llama_token> llama_tokenize(struct llama_context * ctx, const std::s
return res;
}
std::tuple<struct llama_model *, struct llama_context *> llama_init_from_gpt_params(const gpt_params & params) {
struct llama_context_params llama_context_params_from_gpt_params(const gpt_params & params) {
auto lparams = llama_context_default_params();
lparams.n_ctx = params.n_ctx;
@ -551,6 +573,12 @@ std::tuple<struct llama_model *, struct llama_context *> llama_init_from_gpt_par
lparams.logits_all = params.perplexity;
lparams.embedding = params.embedding;
return lparams;
}
std::tuple<struct llama_model *, struct llama_context *> llama_init_from_gpt_params(const gpt_params & params) {
auto lparams = llama_context_params_from_gpt_params(params);
llama_model * model = llama_load_model_from_file(params.model.c_str(), lparams);
if (model == NULL) {
fprintf(stderr, "%s: error: failed to load model '%s'\n", __func__, params.model.c_str());