tweak argparse. fix steps=256, even if some models may support longer maximum seq_len. get rid of seed option for now, use temp=0.0 for deterministic behavior

run.c

@@ -386,28 +386,28 @@ long time_in_ms() {
 int main(int argc, char *argv[]) {
 
     // poor man's C argparse
-    char *checkpoint = NULL;
-    float temperature = 0.9f;
+    char *checkpoint = NULL;  // e.g. out/model.bin
+    float temperature = 0.9f; // e.g. 1.0, or 0.0
+    int steps = 256;          // max number of steps to run for, 0: use seq_len
     // 'checkpoint' is necessary arg
     if (argc < 2) {
-        printf("Usage: %s <checkpoint_file> [temperature] [seed]\n", argv[0]);
+        printf("Usage: %s <checkpoint_file> [temperature] [steps]\n", argv[0]);
         return 1;
     }
+    if (argc >= 2) {
         checkpoint = argv[1];
-    // temperature is optional
+    }
     if (argc >= 3) {
+        // optional temperature. 0.0 = (deterministic) argmax sampling. 1.0 = baseline
         temperature = atof(argv[2]);
     }
-    // seed is optional
     if (argc >= 4) {
-        unsigned int seed = atoi(argv[3]);
-        srand(seed);
-    } else {
-        time_t current_time; 
-        time(&current_time);
-        srand((unsigned int)current_time);
+        steps = atoi(argv[3]);
     }
 
+    // seed rng with time. if you want deterministic behavior use temperature 0.0
+    srand((unsigned int)time(NULL)); 
+    
     // read in the model.bin file
     Config config;
     TransformerWeights weights;
@@ -424,6 +424,8 @@ int main(int argc, char *argv[]) {
         if(checkpoint_init_weights(&weights, &config, file)) { return 1; }
         fclose(file);
     }
+    // right now we cannot 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*));
@@ -450,11 +452,11 @@ int main(int argc, char *argv[]) {
     
     // the current position we are in
     long start = time_in_ms();
-
     int next;
     int token = 1; // 1 = BOS token in Llama-2 sentencepiece
     int pos = 0;
-    while (pos < config.seq_len) {
+    printf("<s>\n"); // explicit print the initial BOS token (=1), stylistically symmetric
+    while (pos < steps) {
 
         // forward the transformer to get logits for the next token
         transformer(token, pos, &config, &state, &weights);
@@ -478,11 +480,10 @@ int main(int argc, char *argv[]) {
         token = next;
         pos++;
     }
-    printf("\n");
 
-    // report our achieved tok/s
+    // report achieved tok/s
     long end = time_in_ms();
-    printf("achieved tok/s: %f\n", config.seq_len / (double)(end-start)*1000);
+    printf("\nachieved tok/s: %f\n", config.seq_len / (double)(end-start)*1000);
 
     // memory cleanup
     free_run_state(&state);