Andrej Karpathy
858 lines
33 KiB
C
858 lines
33 KiB
C
/* Inference for Llama-2 Transformer model in pure C */
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <time.h>
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#include <math.h>
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#include <string.h>
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#include <fcntl.h>
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#if defined _WIN32
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#include "win.h"
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#else
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#include <unistd.h>
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#include <sys/mman.h>
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#endif
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// ----------------------------------------------------------------------------
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// Globals
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int GS = 0; // group size global for quantization of weights
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// ----------------------------------------------------------------------------
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// Transformer and RunState structs, and related memory management
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typedef struct {
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int dim; // transformer dimension
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int hidden_dim; // dimension of the inner layer in the MLP
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int n_layers; // number of layers
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int n_heads; // number of query heads
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int n_kv_heads; // number of key & value heads (can be < query heads because of multiquery)
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int vocab_size; // vocabulary size (size of the classifier weights)
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int seq_len; // max sequence length the model was trained with
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} Config;
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typedef struct {
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int8_t* q; // quantized values
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float* s; // scaling factors
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} QuantizedTensor;
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typedef struct {
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// token embedding table
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QuantizedTensor token_embedding_table; // (vocab_size, dim)
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// weights for rmsnorms
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float* rms_att_weight; // (layer, dim) rmsnorm weights
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float* rms_ffn_weight; // (layer, dim)
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// weights for matmuls. note dim == n_heads * head_size
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QuantizedTensor wq; // (layer, dim, n_heads * head_size)
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QuantizedTensor wk; // (layer, dim, n_kv_heads * head_size)
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QuantizedTensor wv; // (layer, dim, n_kv_heads * head_size)
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QuantizedTensor wo; // (layer, n_heads * head_size, dim)
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// weights for ffn
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QuantizedTensor w1; // (layer, hidden_dim, dim)
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QuantizedTensor w2; // (layer, dim, hidden_dim)
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QuantizedTensor w3; // (layer, hidden_dim, dim)
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// final rmsnorm
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float* rms_final_weight; // (dim,)
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// (optional) classifier weights for the logits, on the last layer
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QuantizedTensor wcls; // (dim, vocab_size)
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} TransformerWeights;
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typedef struct {
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float prob;
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int index;
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} ProbIndex; // struct used when sorting probabilities during top-p sampling
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typedef struct {
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// current wave of activations
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float *x; // activation at current time stamp (dim,)
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float *xb; // same, but inside a residual branch (dim,)
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float *xb2; // an additional buffer just for convenience (dim,)
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float *hb; // buffer for hidden dimension in the ffn (hidden_dim,)
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float *hb2; // buffer for hidden dimension in the ffn (hidden_dim,)
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QuantizedTensor xq; // quantized x (dim,)
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QuantizedTensor hq; // quantized hb (hidden_dim,)
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float *q; // query (dim,)
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float *k; // key (dim,)
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float *v; // value (dim,)
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float *att; // buffer for scores/attention values (n_heads, seq_len)
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float *logits; // output logits
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ProbIndex *probindex; // buffer used in top-p sampling
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// kv cache
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float* key_cache; // (layer, seq_len, dim)
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float* value_cache; // (layer, seq_len, dim)
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} RunState;
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void malloc_run_state(RunState* s, Config* p) {
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// we calloc instead of malloc to keep valgrind happy
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int kv_dim = (p->dim * p->n_kv_heads) / p->n_heads;
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s->x = calloc(p->dim, sizeof(float));
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s->xb = calloc(p->dim, sizeof(float));
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s->xb2 = calloc(p->dim, sizeof(float));
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s->hb = calloc(p->hidden_dim, sizeof(float));
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s->hb2 = calloc(p->hidden_dim, sizeof(float));
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s->xq = (QuantizedTensor) { .q = calloc(p->dim, sizeof(int8_t)), .s = calloc(p->dim, sizeof(float)) };
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s->hq = (QuantizedTensor) { .q = calloc(p->hidden_dim, sizeof(int8_t)), .s = calloc(p->hidden_dim, sizeof(float)) };
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s->q = calloc(p->dim, sizeof(float));
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s->k = calloc(kv_dim, sizeof(float));
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s->v = calloc(kv_dim, sizeof(float));
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s->att = calloc(p->n_heads * p->seq_len, sizeof(float));
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s->logits = calloc(p->vocab_size, sizeof(float));
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s->probindex = calloc(p->vocab_size, sizeof(ProbIndex));
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s->key_cache = calloc(p->n_layers * p->seq_len * kv_dim, sizeof(float));
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s->value_cache = calloc(p->n_layers * p->seq_len * kv_dim, sizeof(float));
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// ensure all mallocs went fine
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if (!s->x || !s->xb || !s->xb2 || !s->hb || !s->hb2 || !s->q
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|| !s->k || !s->v || !s->att || !s->logits || !s->key_cache
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|| !s->value_cache || !s->probindex) {
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fprintf(stderr, "malloc failed!\n");
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exit(EXIT_FAILURE);
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}
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}
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void free_run_state(RunState* s) {
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free(s->x);
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free(s->xb);
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free(s->xb2);
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free(s->hb);
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free(s->hb2);
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free(s->xq.q);
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free(s->xq.s);
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free(s->hq.q);
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free(s->hq.s);
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free(s->q);
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free(s->k);
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free(s->v);
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free(s->att);
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free(s->logits);
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free(s->probindex);
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free(s->key_cache);
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free(s->value_cache);
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}
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// ----------------------------------------------------------------------------
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// initialization: read from checkpoint
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void checkpoint_init_weights(TransformerWeights *w, Config* p, void* ptr, uint8_t shared_classifier) {
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int head_size = p->dim / p->n_heads;
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// first are the parameters that are kept in fp32 (the rmsnorm (1D) weights)
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float* fptr = (float*) ptr; // cast our pointer to float*
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w->rms_att_weight = fptr;
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fptr += p->n_layers * p->dim;
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w->rms_ffn_weight = fptr;
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fptr += p->n_layers * p->dim;
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w->rms_final_weight = fptr;
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fptr += p->dim;
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// now read all the quantized weights
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int8_t* qptr = (int8_t*) fptr; // now cast the pointer to int8_t*
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w->token_embedding_table.q = qptr;
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qptr += p->vocab_size * p->dim;
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w->wq.q = qptr;
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qptr += p->n_layers * p->dim * (p->n_heads * head_size);
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w->wk.q = qptr;
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qptr += p->n_layers * p->dim * (p->n_kv_heads * head_size);
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w->wv.q = qptr;
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qptr += p->n_layers * p->dim * (p->n_kv_heads * head_size);
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w->wo.q = qptr;
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qptr += p->n_layers * (p->n_heads * head_size) * p->dim;
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w->w1.q = qptr;
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qptr += p->n_layers * p->dim * p->hidden_dim;
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w->w2.q = qptr;
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qptr += p->n_layers * p->hidden_dim * p->dim;
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w->w3.q = qptr;
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qptr += p->n_layers * p->dim * p->hidden_dim;
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if (shared_classifier) {
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w->wcls.q = w->token_embedding_table.q;
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} else {
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w->wcls.q = qptr;
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qptr += p->dim * p->vocab_size;
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}
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// and finally all the associated scaling factors
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float* sptr = (float*) qptr; // cast pointer back to float*
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w->token_embedding_table.s = sptr;
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sptr += p->vocab_size * p->dim / GS;
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w->wq.s = sptr;
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sptr += p->n_layers * p->dim * (p->n_heads * head_size) / GS;
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w->wk.s = sptr;
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sptr += p->n_layers * p->dim * (p->n_kv_heads * head_size) / GS;
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w->wv.s = sptr;
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sptr += p->n_layers * p->dim * (p->n_kv_heads * head_size) / GS;
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w->wo.s = sptr;
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sptr += p->n_layers * (p->n_heads * head_size) * p->dim / GS;
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w->w1.s = sptr;
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sptr += p->n_layers * p->dim * p->hidden_dim / GS;
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w->w2.s = sptr;
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sptr += p->n_layers * p->hidden_dim * p->dim / GS;
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w->w3.s = sptr;
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sptr += p->n_layers * p->dim * p->hidden_dim / GS;
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if (shared_classifier) {
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w->wcls.s = w->token_embedding_table.s;
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} else {
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w->wcls.s = sptr;
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sptr += p->dim * p->vocab_size / GS;
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}
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}
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// ----------------------------------------------------------------------------
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// neural net blocks
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void rmsnorm(float* o, float* x, float* weight, int size) {
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// calculate sum of squares
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float ss = 0.0f;
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for (int j = 0; j < size; j++) {
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ss += x[j] * x[j];
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}
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ss /= size;
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ss += 1e-5f;
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ss = 1.0f / sqrtf(ss);
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// normalize and scale
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for (int j = 0; j < size; j++) {
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o[j] = weight[j] * (ss * x[j]);
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}
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}
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void softmax(float* x, int size) {
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// find max value (for numerical stability)
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float max_val = x[0];
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for (int i = 1; i < size; i++) {
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if (x[i] > max_val) {
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max_val = x[i];
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}
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}
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// exp and sum
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float sum = 0.0f;
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for (int i = 0; i < size; i++) {
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x[i] = expf(x[i] - max_val);
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sum += x[i];
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}
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// normalize
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for (int i = 0; i < size; i++) {
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x[i] /= sum;
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}
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}
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void matmul(float* xout, int8_t* xq, float* xs, int8_t* wq, float* ws, int n, int d) {
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// W (d,n) @ x (n,) -> xout (d,)
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// by far the most amount of time is spent inside this little function
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// inputs to this function are both quantized
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int i;
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#pragma omp parallel for private(i)
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for (i = 0; i < d; i++) {
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float val = 0.0f;
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int32_t ival = 0;
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int in = i * n;
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// do the matmul in groups of GS
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int j;
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for (j = 0; j <= n - GS; j += GS) {
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for (int k = 0; k < GS; k++) {
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ival += ((int32_t) xq[j + k]) * ((int32_t) wq[in + j + k]);
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}
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val += ((float) ival) * ws[(in + j) / GS] * xs[j / GS];
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ival = 0;
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}
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xout[i] = val;
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}
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}
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void dequantize(int8_t* q, float* s, float* x, int n) {
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for (int i = 0; i < n; i++) {
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x[i] = q[i] * s[i / GS];
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}
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}
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void quantize(float* x, int8_t* q, float* s, int n) {
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int num_groups = n / GS;
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float Q_MAX = 127.0f;
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for (int group = 0; group < num_groups; group++) {
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// find the max absolute value in the current group
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float wmax = 0.0;
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for (int i = 0; i < GS; i++) {
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float val = fabs(x[group * GS + i]);
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if (val > wmax) {
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wmax = val;
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}
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}
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// calculate and write the scaling factor
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float scale = wmax / Q_MAX;
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s[group] = scale;
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// calculate and write the quantized values
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for (int i = 0; i < GS; i++) {
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float quant_value = x[group * GS + i] / scale; // scale
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int8_t quantized = (int8_t) round(quant_value); // round and clamp
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q[group * GS + i] = quantized;
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}
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}
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}
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void transformer(int token, int pos, Config* p, RunState* s, TransformerWeights* w) {
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// a few convenience variables
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float *x = s->x;
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int dim = p->dim;
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int kv_dim = (p->dim * p->n_kv_heads) / p->n_heads;
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int kv_mul = p->n_heads / p->n_kv_heads; // integer multiplier of the kv sharing in multiquery
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int hidden_dim = p->hidden_dim;
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int head_size = dim / p->n_heads;
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// dequantize the token embedding into a float x
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QuantizedTensor tok = w->token_embedding_table;
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dequantize(tok.q + token * dim, tok.s + token * dim / GS, x, dim);
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// forward all the layers
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for(int l = 0; l < p->n_layers; l++) {
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// attention rmsnorm
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rmsnorm(s->xb, x, w->rms_att_weight + l*dim, dim);
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// qkv matmuls for this position
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quantize(s->xb, s->xq.q, s->xq.s, dim);
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matmul(s->q, s->xq.q, s->xq.s, w->wq.q + l*dim*dim, w->wq.s + l*dim*dim/GS, dim, dim);
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matmul(s->k, s->xq.q, s->xq.s, w->wk.q + l*dim*kv_dim, w->wk.s + l*dim*kv_dim/GS, dim, kv_dim);
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matmul(s->v, s->xq.q, s->xq.s, w->wv.q + l*dim*kv_dim, w->wv.s + l*dim*kv_dim/GS, dim, kv_dim);
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// RoPE relative positional encoding: complex-valued rotate q and k in each head
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for (int i = 0; i < dim; i+=2) {
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int head_dim = i % head_size;
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float freq = 1.0f / powf(10000.0f, head_dim / (float)head_size);
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float val = pos * freq;
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float fcr = cosf(val);
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float fci = sinf(val);
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int rotn = i < kv_dim ? 2 : 1; // how many vectors? 2 = q & k, 1 = q only
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for (int v = 0; v < rotn; v++) {
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float* vec = v == 0 ? s->q : s->k; // the vector to rotate (query or key)
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float v0 = vec[i];
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float v1 = vec[i+1];
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vec[i] = v0 * fcr - v1 * fci;
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vec[i+1] = v0 * fci + v1 * fcr;
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}
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}
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// save key,value at this time step (pos) to our kv cache
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int loff = l * p->seq_len * kv_dim; // kv cache layer offset for convenience
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float* key_cache_row = s->key_cache + loff + pos * kv_dim;
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float* value_cache_row = s->value_cache + loff + pos * kv_dim;
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memcpy(key_cache_row, s->k, kv_dim * sizeof(*key_cache_row));
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memcpy(value_cache_row, s->v, kv_dim * sizeof(*value_cache_row));
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// multihead attention. iterate over all heads
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int h;
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#pragma omp parallel for private(h)
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for (h = 0; h < p->n_heads; h++) {
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// get the query vector for this head
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float* q = s->q + h * head_size;
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// attention scores for this head
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float* att = s->att + h * p->seq_len;
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// iterate over all timesteps, including the current one
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for (int t = 0; t <= pos; t++) {
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// get the key vector for this head and at this timestep
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float* k = s->key_cache + loff + t * kv_dim + (h / kv_mul) * head_size;
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// calculate the attention score as the dot product of q and k
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float score = 0.0f;
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for (int i = 0; i < head_size; i++) {
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score += q[i] * k[i];
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}
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score /= sqrtf(head_size);
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// save the score to the attention buffer
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att[t] = score;
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}
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// softmax the scores to get attention weights, from 0..pos inclusively
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softmax(att, pos + 1);
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// weighted sum of the values, store back into xb
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float* xb = s->xb + h * head_size;
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memset(xb, 0, head_size * sizeof(float));
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for (int t = 0; t <= pos; t++) {
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// get the value vector for this head and at this timestep
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float* v = s->value_cache + loff + t * kv_dim + (h / kv_mul) * head_size;
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// get the attention weight for this timestep
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float a = att[t];
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// accumulate the weighted value into xb
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for (int i = 0; i < head_size; i++) {
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xb[i] += a * v[i];
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}
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}
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}
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// final matmul to get the output of the attention
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quantize(s->xb, s->xq.q, s->xq.s, dim);
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matmul(s->xb2, s->xq.q, s->xq.s, w->wo.q + l*dim*dim, w->wo.s + l*dim*dim/GS, dim, dim);
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// residual connection back into x
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for (int i = 0; i < dim; i++) {
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x[i] += s->xb2[i];
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}
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// ffn rmsnorm
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rmsnorm(s->xb, x, w->rms_ffn_weight + l*dim, dim);
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// Now for FFN in PyTorch we have: self.w2(F.silu(self.w1(x)) * self.w3(x))
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// first calculate self.w1(x) and self.w3(x)
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quantize(s->xb, s->xq.q, s->xq.s, dim);
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matmul(s->hb, s->xq.q, s->xq.s, w->w1.q + l*dim*hidden_dim, w->w1.s + l*dim*hidden_dim/GS, dim, hidden_dim);
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matmul(s->hb2, s->xq.q, s->xq.s, w->w3.q + l*dim*hidden_dim, w->w3.s + l*dim*hidden_dim/GS, dim, hidden_dim);
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// F.silu; silu(x)=x*σ(x),where σ(x) is the logistic sigmoid
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for (int i = 0; i < hidden_dim; i++) {
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s->hb[i] = s->hb[i] * (1.0f / (1.0f + expf(-s->hb[i])));
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}
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// elementwise multiply with w3(x)
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for (int i = 0; i < hidden_dim; i++) {
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s->hb[i] = s->hb[i] * s->hb2[i];
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}
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// final matmul to get the output of the ffn
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quantize(s->hb, s->hq.q, s->hq.s, hidden_dim);
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matmul(s->xb, s->hq.q, s->hq.s, w->w2.q + l*dim*hidden_dim, w->w2.s + l*dim*hidden_dim/GS, hidden_dim, dim);
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// residual connection
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for (int i = 0; i < dim; i++) {
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||
x[i] += s->xb[i];
|
||
}
|
||
}
|
||
|
||
// final rmsnorm
|
||
rmsnorm(x, x, w->rms_final_weight, dim);
|
||
|
||
// classifier into logits
|
||
quantize(x, s->xq.q, s->xq.s, dim);
|
||
matmul(s->logits, s->xq.q, s->xq.s, w->wcls.q, w->wcls.s, dim, p->vocab_size);
|
||
}
|
||
|
||
// ----------------------------------------------------------------------------
|
||
// byte pair encoding (BPE) tokenizer, encodes strings into tokens so we can prompt
|
||
|
||
typedef struct {
|
||
char *str;
|
||
int id;
|
||
} TokenIndex;
|
||
|
||
int compare_tokens(const void *a, const void *b) {
|
||
return strcmp(((TokenIndex*)a)->str, ((TokenIndex*)b)->str);
|
||
}
|
||
|
||
int str_lookup(char *str, TokenIndex *sorted_vocab, int vocab_size) {
|
||
// efficiently find the perfect match for str in vocab, return its index or -1 if not found
|
||
TokenIndex tok = { .str = str }; // acts as the key to search for
|
||
TokenIndex *res = bsearch(&tok, sorted_vocab, vocab_size, sizeof(TokenIndex), compare_tokens);
|
||
return res != NULL ? res->id : -1;
|
||
}
|
||
|
||
void bpe_encode(char *text, char **vocab, float *vocab_scores, int vocab_size, unsigned int max_token_length, int *tokens, int *n_tokens) {
|
||
|
||
// sort vocabulary
|
||
TokenIndex *sorted_vocab = malloc(vocab_size * sizeof(TokenIndex));
|
||
for (int i = 0; i < vocab_size; i++) {
|
||
sorted_vocab[i].str = vocab[i];
|
||
sorted_vocab[i].id = i;
|
||
}
|
||
qsort(sorted_vocab, vocab_size, sizeof(TokenIndex), compare_tokens);
|
||
|
||
// create a temporary buffer that will store merge candidates of always two consecutive tokens
|
||
char* str_buffer = malloc((max_token_length*2 +1 +2) * sizeof(char)); // *2 for concat, +1 for null terminator +2 for UTF8 (in case max_token_lenght is 1)
|
||
size_t str_len = 0;
|
||
|
||
// add_dummy_prefix is true by default
|
||
tokens[0] = str_lookup(" ", sorted_vocab, vocab_size);
|
||
*n_tokens = 1; // the number of tokens
|
||
|
||
// Okay UTF-8 time. This will get messy. Here is the reference from Wikipedia:
|
||
// Code point ↔ UTF-8 conversion
|
||
// First code point Last code point Byte 1 Byte 2 Byte 3 Byte 4
|
||
// U+0000 U+007F 0xxxxxxx
|
||
// U+0080 U+07FF 110xxxxx 10xxxxxx
|
||
// U+0800 U+FFFF 1110xxxx 10xxxxxx 10xxxxxx
|
||
// U+10000 U+10FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
|
||
|
||
// process the raw (UTF-8) byte sequence of the input string
|
||
for (char *c = text; *c != '\0'; c++) {
|
||
|
||
// reset buffer if the current byte is ASCII or a leading byte
|
||
// 0xC0 is 11000000, so (*c & 0xC0) keeps the first 2 bits and zeros the rest
|
||
// 0x80 is 10000000
|
||
// in UTF-8, all continuation bytes start with "10" in first two bits
|
||
// so in English this is: "if this byte is not a continuation byte"
|
||
if ((*c & 0xC0) != 0x80) {
|
||
// this byte must be either a leading byte (11...) or an ASCII char (0x...)
|
||
// => reset our location, as we're starting a new UTF-8 codepoint
|
||
str_len = 0;
|
||
}
|
||
|
||
// append the current byte to the buffer
|
||
str_buffer[str_len++] = *c; // ++ is post-increment, incremented after this line
|
||
str_buffer[str_len] = '\0';
|
||
|
||
// while the next character is a continuation byte, continue appending
|
||
// but if there are too many of them, just stop to avoid overruning str_buffer size.
|
||
if ((*(c+1) & 0xC0) == 0x80 && str_len < 4) {
|
||
continue;
|
||
}
|
||
|
||
// ok c+1 is not a continuation byte, so we've read in a full codepoint
|
||
int id = str_lookup(str_buffer, sorted_vocab, vocab_size);
|
||
|
||
if (id != -1) {
|
||
// we found this codepoint in vocab, add it as a token
|
||
tokens[(*n_tokens)++] = id;
|
||
} else {
|
||
// byte_fallback encoding: just encode each byte as a token
|
||
// +3 is here because the first 3 vocab elements are <unk>, <s>, </s>
|
||
// so the individual bytes only start at index 3
|
||
for (int i=0; i < str_len; i++) {
|
||
tokens[(*n_tokens)++] = (unsigned char)str_buffer[i] + 3;
|
||
}
|
||
}
|
||
str_len = 0; // protect against a sequence of stray UTF8 continuation bytes
|
||
}
|
||
|
||
// merge the best consecutive pair each iteration, according the scores in vocab_scores
|
||
while (1) {
|
||
float best_score = -1e10;
|
||
int best_id = -1;
|
||
int best_idx = -1;
|
||
|
||
for (int i=0; i < (*n_tokens-1); i++) {
|
||
// check if we can merge the pair (tokens[i], tokens[i+1])
|
||
sprintf(str_buffer, "%s%s", vocab[tokens[i]], vocab[tokens[i+1]]);
|
||
int id = str_lookup(str_buffer, sorted_vocab, vocab_size);
|
||
if (id != -1 && vocab_scores[id] > best_score) {
|
||
// this merge pair exists in vocab! record its score and position
|
||
best_score = vocab_scores[id];
|
||
best_id = id;
|
||
best_idx = i;
|
||
}
|
||
}
|
||
|
||
if (best_idx == -1) {
|
||
break; // we couldn't find any more pairs to merge, so we're done
|
||
}
|
||
|
||
// merge the consecutive pair (best_idx, best_idx+1) into new token best_id
|
||
tokens[best_idx] = best_id;
|
||
// delete token at position best_idx+1, shift the entire sequence back 1
|
||
for (int i = best_idx+1; i < (*n_tokens-1); i++) {
|
||
tokens[i] = tokens[i+1];
|
||
}
|
||
(*n_tokens)--; // token length decreased
|
||
}
|
||
|
||
free(str_buffer);
|
||
free(sorted_vocab);
|
||
}
|
||
|
||
// ----------------------------------------------------------------------------
|
||
// utilities: time / rng
|
||
|
||
long time_in_ms() {
|
||
// return time in milliseconds, for benchmarking the model speed
|
||
struct timespec time;
|
||
clock_gettime(CLOCK_REALTIME, &time);
|
||
return time.tv_sec * 1000 + time.tv_nsec / 1000000;
|
||
}
|
||
|
||
unsigned long long rng_seed;
|
||
unsigned int random_u32() {
|
||
// xorshift rng: https://en.wikipedia.org/wiki/Xorshift#xorshift.2A
|
||
rng_seed ^= rng_seed >> 12;
|
||
rng_seed ^= rng_seed << 25;
|
||
rng_seed ^= rng_seed >> 27;
|
||
return (rng_seed * 0x2545F4914F6CDD1Dull) >> 32;
|
||
}
|
||
float random_f32() { // random float32 in [0,1)
|
||
return (random_u32() >> 8) / 16777216.0f;
|
||
}
|
||
|
||
// ----------------------------------------------------------------------------
|
||
// sampling can be done in a few ways: greedy argmax, sampling, top-p sampling
|
||
|
||
int argmax(float* probabilities, int n) {
|
||
// return the index that has the highest probability
|
||
int max_i = 0;
|
||
float max_p = probabilities[0];
|
||
for (int i = 1; i < n; i++) {
|
||
if (probabilities[i] > max_p) {
|
||
max_i = i;
|
||
max_p = probabilities[i];
|
||
}
|
||
}
|
||
return max_i;
|
||
}
|
||
|
||
int sample(float* probabilities, int n) {
|
||
// sample index from probabilities (they must sum to 1!)
|
||
float r = random_f32();
|
||
float cdf = 0.0f;
|
||
for (int i = 0; i < n; i++) {
|
||
cdf += probabilities[i];
|
||
if (r < cdf) {
|
||
return i;
|
||
}
|
||
}
|
||
return n - 1; // in case of rounding errors
|
||
}
|
||
|
||
int compare(const void* a, const void* b) {
|
||
ProbIndex* a_ = (ProbIndex*) a;
|
||
ProbIndex* b_ = (ProbIndex*) b;
|
||
if (a_->prob > b_->prob) return -1;
|
||
if (a_->prob < b_->prob) return 1;
|
||
return 0;
|
||
}
|
||
|
||
int sample_topp(float* probabilities, int n, float topp, ProbIndex* probindex) {
|
||
// top-p sampling (or "nucleus sampling") samples from the smallest set of
|
||
// tokens that exceed probability topp. This way we never sample tokens that
|
||
// have very low probabilities and are less likely to go "off the rails".
|
||
|
||
int n0 = 0;
|
||
// quicksort indices in descending order of probabilities
|
||
// values smaller than (1 - topp) / (n - 1) cannot be part of the result
|
||
// so for efficiency we crop these out as candidates before sorting
|
||
const float cutoff = (1.0f - topp) / (n - 1);
|
||
for (int i = 0; i < n; i++) {
|
||
if (probabilities[i] >= cutoff) {
|
||
probindex[n0].index = i;
|
||
probindex[n0].prob = probabilities[i];
|
||
n0++;
|
||
}
|
||
}
|
||
qsort(probindex, n0, sizeof(ProbIndex), compare);
|
||
|
||
// truncate the list where cumulative probability exceeds topp
|
||
float cumulative_prob = 0.0f;
|
||
int last_idx = n0 - 1; // in case of rounding errors consider all elements
|
||
for (int i = 0; i < n0; i++) {
|
||
cumulative_prob += probindex[i].prob;
|
||
if (cumulative_prob > topp) {
|
||
last_idx = i;
|
||
break; // we've exceeded topp by including last_idx
|
||
}
|
||
}
|
||
|
||
// sample from the truncated list
|
||
float r = random_f32() * cumulative_prob;
|
||
float cdf = 0.0f;
|
||
for (int i = 0; i <= last_idx; i++) {
|
||
cdf += probindex[i].prob;
|
||
if (r < cdf) {
|
||
return probindex[i].index;
|
||
}
|
||
}
|
||
return probindex[last_idx].index; // in case of rounding errors
|
||
}
|
||
|
||
|
||
// ----------------------------------------------------------------------------
|
||
// int main
|
||
|
||
void error_usage() {
|
||
fprintf(stderr, "Usage: run <checkpoint> [options]\n");
|
||
fprintf(stderr, "Example: run model.bin -n 256 -i \"Once upon a time\"\n");
|
||
fprintf(stderr, "Options:\n");
|
||
fprintf(stderr, " -t <float> temperature, default 1.0\n");
|
||
fprintf(stderr, " -p <float> p value in top-p (nucleus) sampling. default 0.9\n");
|
||
fprintf(stderr, " -s <int> random seed, default time(NULL)\n");
|
||
fprintf(stderr, " -n <int> number of steps to run for, default 256. 0 = max_seq_len\n");
|
||
fprintf(stderr, " -i <string> input prompt\n");
|
||
fprintf(stderr, " -z <string> optional path to custom tokenizer\n");
|
||
exit(EXIT_FAILURE);
|
||
}
|
||
|
||
int main(int argc, char *argv[]) {
|
||
|
||
// default inits
|
||
char *checkpoint = NULL; // e.g. out/model.bin
|
||
char *tokenizer = "tokenizer.bin";
|
||
float temperature = 1.0f; // 0.0 = greedy deterministic. 1.0 = original. don't set higher
|
||
float topp = 0.9f; // top-p in nucleus sampling. 1.0 = off. 0.9 works well, but slower
|
||
rng_seed = 0; // seed rng with time by default
|
||
int steps = 256; // number of steps to run for
|
||
char *prompt = NULL; // prompt string
|
||
|
||
// poor man's C argparse so we can override the defaults above from the command line
|
||
if (argc >= 2) { checkpoint = argv[1]; } else { error_usage(); }
|
||
for (int i = 2; i < argc; i+=2) {
|
||
// do some basic validation
|
||
if (i + 1 >= argc) { error_usage(); } // must have arg after flag
|
||
if (argv[i][0] != '-') { error_usage(); } // must start with dash
|
||
if (strlen(argv[i]) != 2) { error_usage(); } // must be -x (one dash, one letter)
|
||
// read in the args
|
||
if (argv[i][1] == 't') { temperature = atof(argv[i + 1]); }
|
||
else if (argv[i][1] == 'p') { topp = atof(argv[i + 1]); }
|
||
else if (argv[i][1] == 's') { rng_seed = atoi(argv[i + 1]); }
|
||
else if (argv[i][1] == 'n') { steps = atoi(argv[i + 1]); }
|
||
else if (argv[i][1] == 'i') { prompt = argv[i + 1]; }
|
||
else if (argv[i][1] == 'z') { tokenizer = argv[i + 1]; }
|
||
else { error_usage(); }
|
||
}
|
||
// input validations
|
||
// our rng cannot accoupt 0 as a seed, so might as well use time(NULL) as default
|
||
if(rng_seed == 0) { rng_seed = (unsigned int)time(NULL); }
|
||
|
||
// read in the model.bin file
|
||
Config config;
|
||
TransformerWeights weights;
|
||
int fd = 0; // file descriptor for memory mapping
|
||
void* data = NULL; // memory mapped data pointer
|
||
ssize_t file_size; // size of the checkpoint file in bytes
|
||
{
|
||
// first "peak" the checkpoint and extract metadata
|
||
FILE *file = fopen(checkpoint, "rb");
|
||
if (!file) { fprintf(stderr, "Couldn't open file %s\n", checkpoint); return 1; }
|
||
// read in magic number (uint32), has to be 0x616b3432, i.e. "ak42" in ASCII
|
||
uint32_t magic_number;
|
||
if (fread(&magic_number, sizeof(uint32_t), 1, file) != 1) { return 1; }
|
||
if (magic_number != 0x616b3432) { fprintf(stderr, "Bad magic number\n"); return 1; }
|
||
// read in the version number (uint32), has to be 1
|
||
int version;
|
||
if (fread(&version, sizeof(int), 1, file) != 1) { return 1; }
|
||
if (version != 1) { fprintf(stderr, "Bad version number\n"); return 1; }
|
||
int header_size = 256; // the header size for version 1 in bytes
|
||
// read in the Config
|
||
if (fread(&config, sizeof(Config), 1, file) != 1) { return 1; }
|
||
// read in flags
|
||
uint8_t shared_classifier; // a byte to indicate if the classifier is shared
|
||
if (fread(&shared_classifier, sizeof(uint8_t), 1, file) != 1) { return 1; }
|
||
int group_size; // the group size used in quantization
|
||
if (fread(&group_size, sizeof(int), 1, file) != 1) { return 1; }
|
||
GS = group_size; // set as global, as it will be used in many places
|
||
// seek all the way to the end to figure out the full file size
|
||
fseek(file, 0, SEEK_END); // move file pointer to end of file
|
||
file_size = ftell(file); // get the file size, in bytes
|
||
fclose(file);
|
||
|
||
// now memory map the Transformer weights into the data pointer
|
||
fd = open(checkpoint, O_RDONLY); // open in read only mode
|
||
if (fd == -1) { fprintf(stderr, "open failed!\n"); return 1; }
|
||
data = mmap(NULL, file_size, PROT_READ, MAP_PRIVATE, fd, 0);
|
||
if (data == MAP_FAILED) { fprintf(stderr, "mmap failed!\n"); return 1; }
|
||
void* weights_ptr = (char*)data + header_size; // skip header bytes. char is 1 byte
|
||
checkpoint_init_weights(&weights, &config, weights_ptr, shared_classifier);
|
||
}
|
||
// we should not run for more than config.seq_len steps
|
||
if (steps <= 0 || steps > config.seq_len) { steps = config.seq_len; }
|
||
|
||
// read in the tokenizer .bin file
|
||
char** vocab = (char**)malloc(config.vocab_size * sizeof(char*));
|
||
float* vocab_scores = (float*)malloc(config.vocab_size * sizeof(float));
|
||
unsigned int max_token_length;
|
||
{
|
||
FILE *file = fopen(tokenizer, "rb");
|
||
if (!file) { fprintf(stderr, "couldn't load %s\n", tokenizer); return 1; }
|
||
if (fread(&max_token_length, sizeof(int), 1, file) != 1) { fprintf(stderr, "failed read\n"); return 1; }
|
||
int len;
|
||
for (int i = 0; i < config.vocab_size; i++) {
|
||
if (fread(vocab_scores + i, sizeof(float), 1, file) != 1) { fprintf(stderr, "failed read\n"); return 1;}
|
||
if (fread(&len, sizeof(int), 1, file) != 1) { fprintf(stderr, "failed read\n"); return 1; }
|
||
vocab[i] = (char *)malloc(len + 1);
|
||
if (fread(vocab[i], len, 1, file) != 1) { fprintf(stderr, "failed read\n"); return 1; }
|
||
vocab[i][len] = '\0'; // add the string terminating token
|
||
}
|
||
fclose(file);
|
||
}
|
||
|
||
// create and init the application RunState
|
||
RunState state;
|
||
malloc_run_state(&state, &config);
|
||
|
||
// process the prompt, if any
|
||
int *prompt_tokens = NULL;
|
||
int num_prompt_tokens = 0;
|
||
if (prompt != NULL) {
|
||
prompt_tokens = (int*)malloc((strlen(prompt)+1) * sizeof(int));
|
||
bpe_encode(prompt, vocab, vocab_scores, config.vocab_size, max_token_length, prompt_tokens, &num_prompt_tokens);
|
||
}
|
||
|
||
// start the main loop
|
||
long start = 0; // used to time our code, only initialized after first iteration
|
||
int next; // will store the next token in the sequence
|
||
int token = 1; // init with token 1 (=BOS), as done in Llama-2 sentencepiece tokenizer
|
||
int pos = 0; // position in the sequence
|
||
while (pos < steps) {
|
||
|
||
// forward the transformer to get logits for the next token
|
||
transformer(token, pos, &config, &state, &weights);
|
||
|
||
// advance the state state machine
|
||
if(pos < num_prompt_tokens) {
|
||
// if we are still processing the input prompt, force the next prompt token
|
||
next = prompt_tokens[pos];
|
||
} else {
|
||
// sample the next token
|
||
if (temperature == 0.0f) {
|
||
// greedy argmax sampling: take the token with the highest probability
|
||
next = argmax(state.logits, config.vocab_size);
|
||
} else {
|
||
// apply the temperature to the logits
|
||
for (int q=0; q<config.vocab_size; q++) { state.logits[q] /= temperature; }
|
||
// apply softmax to the logits to get the probabilities for next token
|
||
softmax(state.logits, config.vocab_size);
|
||
// we sample from this distribution to get the next token
|
||
if (topp <= 0 || topp >= 1) {
|
||
// simply sample from the predicted probability distribution
|
||
next = sample(state.logits, config.vocab_size);
|
||
} else {
|
||
// top-p (nucleus) sampling, clamping the least likely tokens to zero
|
||
next = sample_topp(state.logits, config.vocab_size, topp, state.probindex);
|
||
}
|
||
}
|
||
}
|
||
pos++;
|
||
|
||
// data-dependent terminating condition: the BOS (1) token delimits sequences
|
||
if (next == 1) { break; }
|
||
|
||
// following BOS (1) token, sentencepiece decoder strips any leading whitespace (see PR #89)
|
||
char *token_str = (token == 1 && vocab[next][0] == ' ') ? vocab[next]+1 : vocab[next];
|
||
// careful, some tokens designate raw bytes, and look like e.g. '<0x01>'
|
||
unsigned char byte_val;
|
||
if (sscanf(token_str, "<0x%02hhX>", &byte_val) == 1) {
|
||
// ok this token is a raw byte token, carefuly to only print printable chars or whitespace
|
||
// some of the other bytes can be various control codes, backspace, etc. => skip
|
||
if (isprint(byte_val) || isspace(byte_val)) {
|
||
char byte_piece[2];
|
||
byte_piece[0] = byte_val;
|
||
byte_piece[1] = '\0';
|
||
printf("%s", byte_piece);
|
||
}
|
||
} else {
|
||
printf("%s", token_str);
|
||
}
|
||
fflush(stdout);
|
||
token = next;
|
||
|
||
// init the timer here because the first iteration can be slower
|
||
if (start == 0) { start = time_in_ms(); }
|
||
}
|
||
printf("\n");
|
||
|
||
// report achieved tok/s (pos-1 because the timer starts after first iteration)
|
||
if (pos > 1) {
|
||
long end = time_in_ms();
|
||
fprintf(stderr, "achieved tok/s: %f\n", (pos-1) / (double)(end-start)*1000);
|
||
}
|
||
|
||
// memory and file handles cleanup
|
||
free_run_state(&state);
|
||
for (int i = 0; i < config.vocab_size; i++) { free(vocab[i]); }
|
||
free(vocab);
|
||
free(vocab_scores);
|
||
if (prompt_tokens != NULL) free(prompt_tokens);
|
||
if (data != MAP_FAILED) munmap(data, file_size);
|
||
if (fd != -1) close(fd);
|
||
return 0;
|
||
}
|