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Fix off-by-one errors in generation code and token streaming callback. #127

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Merged
copybara-service merged 1 commit into from
Apr 4, 2024
Merged

Fix off-by-one errors in generation code and token streaming callback. #127

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17 changes: 13 additions & 4 deletions gemma.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -666,12 +666,16 @@ void GenerateImpl(GemmaImpl<TConfig>& gemma, size_t max_tokens,

size_t pos_gen_start = pos_offset;
int token = prompt.at(pos_offset);
stream_token(token, 0);
for (size_t generate_pos = 0;
pos < max_tokens && generate_pos < max_generated_tokens;
++pos, ++pos_offset, ++generate_pos) {
Transformer(token, pos, c_weights, activations, kv_cache, pool, inner_pool);
float* final_activation = activations.x.data();
if (pos_offset >= prompt_size) {
// The condition below is always true if we are doing Prefill above.
// We keep it here for clarity so that the code is correct even if Prefill
// is disabled.
if (pos_offset >= prompt_size - 1) {
PROFILER_ZONE("Gen.Embedding");
// Generation phase
MatVec<kVocabSize, TConfig::kModelDim>(
Expand All @@ -681,9 +685,14 @@ void GenerateImpl(GemmaImpl<TConfig>& gemma, size_t max_tokens,
Softmax(activations.logits.data(), kVocabSize);
token = SampleTopK<TConfig::kTopK>(activations.logits.data(), kVocabSize,
gen, temperature, accept_token);
}
if (!stream_token(token, activations.logits[token])) {
token = EOS_ID;
if (!stream_token(token, activations.logits[token])) {
token = EOS_ID;
}
} else {
// We would take this branch if we were not doing Prefill but would
// process the tokens of the prompt one at a time.
token = prompt.at(pos_offset + 1);
stream_token(token, 0);
}
if (token == EOS_ID) {
if (verbosity >= 2) {
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3 changes: 2 additions & 1 deletion run.cc
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Expand Up @@ -116,7 +116,8 @@ void ReplGemma(gcpp::Gemma& model, gcpp::KVCache& kv_cache,
verbosity](int token, float) {
++abs_pos;
++current_pos;
if (current_pos < prompt_size) {
// <= since position is incremented before
if (current_pos <= prompt_size) {
std::cerr << "." << std::flush;
} else if (token == gcpp::EOS_ID) {
if (!args.multiturn) {
Expand Down