Overhaul the examples structure

- main -> examples
- utils -> examples (renamed to "common")
- quantize -> examples
- separate tools for "perplexity" and "embedding"

Hope I didn't break something !

3 files changed, 153 insertions, 0 deletions

diff --git a/examples/perplexity/CMakeLists.txt b/examples/perplexity/CMakeLists.txt
new file mode 100644
index 0000000..5836df8
--- /dev/null
+++ b/examples/perplexity/CMakeLists.txt
@@ -0,0 +1,4 @@
+set(TARGET perplexity)
+add_executable(${TARGET} perplexity.cpp)
+target_link_libraries(${TARGET} PRIVATE common llama ${CMAKE_THREAD_LIBS_INIT})
+target_compile_features(${TARGET} PRIVATE cxx_std_11)
diff --git a/examples/perplexity/README.md b/examples/perplexity/README.md
new file mode 100644
index 0000000..a932275
--- /dev/null
+++ b/examples/perplexity/README.md
@@ -0,0 +1,3 @@
+# perplexity

+

+TODO

diff --git a/examples/perplexity/perplexity.cpp b/examples/perplexity/perplexity.cpp
new file mode 100644
index 0000000..f0266a0
--- /dev/null
+++ b/examples/perplexity/perplexity.cpp
@@ -0,0 +1,146 @@
+#include "common.h"
+#include "llama.h"
+
+#include <cassert>
+#include <cinttypes>
+#include <cmath>
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <vector>
+
+std::vector<double> softmax(const std::vector<float>& logits) {
+    std::vector<double> probs(logits.size());
+    float max_logit = logits[0];
+    for (float v : logits) max_logit = std::max(max_logit, v);
+    double sum_exp = 0.0;
+    for (size_t i = 0; i < logits.size(); i++) {
+        // Subtract the maximum logit value from the current logit value for numerical stability
+        float logit = logits[i] - max_logit;
+        double exp_logit = std::exp(logit);
+        sum_exp += exp_logit;
+        probs[i] = exp_logit;
+    }
+    for (size_t i = 0; i < probs.size(); i++) probs[i] /= sum_exp;
+    return probs;
+}
+
+void perplexity(llama_context * ctx, const gpt_params & params) {
+    // Download: https://s3.amazonaws.com/research.metamind.io/wikitext/wikitext-2-raw-v1.zip?ref=salesforce-research
+    // Run `./main --perplexity -m models/7B/ggml-model-q4_0.bin -f wiki.test.raw`
+    // Output: `perplexity: 13.5106 [114/114]`
+    auto tokens = ::llama_tokenize(ctx, params.prompt, true);
+
+    int count = 0;
+    double nll = 0.0;
+    int seq_count = tokens.size() / params.n_ctx;
+
+    fprintf(stderr, "%s : calculating perplexity over %d chunks\n", __func__, seq_count);
+
+    for (int i = 0; i < seq_count; ++i) {
+        int start = i * params.n_ctx;
+        int end = start + params.n_ctx - 1;
+        std::vector<llama_token> embd(tokens.begin() + start, tokens.begin() + end);
+        auto start_t = std::chrono::high_resolution_clock::now();
+        if (llama_eval(ctx, embd.data(), embd.size(), 0, params.n_threads)) {
+            fprintf(stderr, "%s : failed to eval\n", __func__);
+            return;
+        }
+        auto end_t = std::chrono::high_resolution_clock::now();
+        if (i == 0) {
+            double seconds = std::chrono::duration<double>(end_t - start_t).count();
+            printf("%.2f seconds per pass - ETA %.2f hours\n", seconds, (seconds * seq_count) / (60.0*60.0));
+        }
+        // We get the logits for all the tokens in the context window (params.n_ctx)
+        // from llama_eval above.  Now, based on https://huggingface.co/docs/transformers/perplexity,
+        // calculate the perplexity over the last half the window (so the model always has
+        // some context to predict the token).
+        //
+        // We rely on the fact that attention in the forward pass only looks at previous
+        // tokens here, so the logits returned for each token are an accurate representation
+        // of what the model would have predicted at that point.
+        //
+        // Example, we have a context window of 512, we will compute perplexity for each of the
+        // last 256 tokens.  Then, we split the input up into context window size chunks to
+        // process the entire prompt.
+
+        auto logits = llama_get_logits(ctx);
+        for (int j = params.n_ctx / 2; j < params.n_ctx - 1; ++j) {
+            // Calculate probability of next token, given the previous ones.
+            int n_vocab = llama_n_vocab(ctx);
+            std::vector<float> tok_logits(
+                logits + j * n_vocab,
+                logits + (j + 1) * n_vocab);
+            double prob = softmax(tok_logits)[tokens[start + j + 1]];
+            nll += -std::log(prob);
+            ++count;
+        }
+        // perplexity is e^(average negative log-likelihood)
+        printf("[%d]%.4lf,", i + 1, std::exp(nll / count));
+        fflush(stdout);
+    }
+    printf("\n");
+}
+
+int main(int argc, char ** argv) {
+    gpt_params params;
+    params.model = "models/llama-7B/ggml-model.bin";
+
+    if (gpt_params_parse(argc, argv, params) == false) {
+        return 1;
+    }
+
+    params.perplexity = true;
+
+    if (params.n_ctx > 2048) {
+        fprintf(stderr, "%s: warning: model does not support context sizes greater than 2048 tokens (%d specified);"
+                "expect poor results\n", __func__, params.n_ctx);
+    }
+
+    if (params.seed <= 0) {
+        params.seed = time(NULL);
+    }
+
+    fprintf(stderr, "%s: seed = %d\n", __func__, params.seed);
+
+    std::mt19937 rng(params.seed);
+    if (params.random_prompt) {
+        params.prompt = gpt_random_prompt(rng);
+    }
+
+    llama_context * ctx;
+
+    // load the model
+    {
+        auto lparams = llama_context_default_params();
+
+        lparams.n_ctx      = params.n_ctx;
+        lparams.n_parts    = params.n_parts;
+        lparams.seed       = params.seed;
+        lparams.f16_kv     = params.memory_f16;
+        lparams.logits_all = params.perplexity;
+        lparams.use_mlock  = params.use_mlock;
+        lparams.embedding  = params.embedding;
+
+        ctx = llama_init_from_file(params.model.c_str(), lparams);
+
+        if (ctx == NULL) {
+            fprintf(stderr, "%s: error: failed to load model '%s'\n", __func__, params.model.c_str());
+            return 1;
+        }
+    }
+
+    // print system information
+    {
+        fprintf(stderr, "\n");
+        fprintf(stderr, "system_info: n_threads = %d / %d | %s\n",
+                params.n_threads, std::thread::hardware_concurrency(), llama_print_system_info());
+    }
+
+    perplexity(ctx, params);
+
+    llama_print_timings(ctx);
+    llama_free(ctx);
+
+    return 0;
+}