server: fix incorrectly reported token probabilities (#7125)

* server: normalize token probabilities

* fix temperature == 0.0f
This commit is contained in:
Johannes Gäßler 2024-05-07 23:07:58 +02:00 committed by GitHub
parent b6aa670203
commit af0a5b6163
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4 changed files with 31 additions and 11 deletions

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@ -2266,17 +2266,31 @@ struct server_context {
llama_token_data_array cur_p = { slot.ctx_sampling->cur.data(), slot.ctx_sampling->cur.size(), false };
result.tok = id;
const int32_t n_probs = slot.sparams.n_probs;
if (slot.sparams.temp <= 0 && n_probs > 0) {
// for llama_sample_token_greedy we need to sort candidates
llama_sample_softmax(ctx, &cur_p);
}
const size_t n_probs = std::min(cur_p.size, (size_t) slot.sparams.n_probs);
if (n_probs > 0) {
const size_t n_considered = slot.ctx_sampling->n_considered;
for (size_t i = 0; i < std::min(cur_p.size, (size_t) n_probs); ++i) {
result.probs.push_back({
cur_p.data[i].id,
cur_p.data[i].p
});
// Make sure at least n_probs top tokens are at the front of the vector:
if (slot.sparams.temp == 0.0f && n_probs > n_considered) {
llama_sample_top_k(ctx, &cur_p, n_probs, 0);
}
if (slot.sparams.temp == 0.0f) {
// With greedy sampling the probabilities have possibly not been calculated.
for (size_t i = 0; i < n_probs; ++i) {
result.probs.push_back({
cur_p.data[i].id,
i == 0 ? 1.0f : 0.0f
});
}
} else {
for (size_t i = 0; i < n_probs; ++i) {
result.probs.push_back({
cur_p.data[i].id,
i >= n_considered ? 0.0f : cur_p.data[i].p // Tokens filtered out due to e.g. top_k have 0 probability.
});
}
}
}
if (!process_token(result, slot)) {