print error on insufficient batch size

examples/retrieval/retrieval.cpp

@@ -171,7 +171,9 @@ int main(int argc, char ** argv) {
     for (auto & chunk : chunks) {
         auto inp = ::llama_tokenize(ctx, chunk.textdata, true, false);
         if (inp.size() > n_batch) {
-            inp.resize(n_batch);
+            // error: chunk size exceeds batch size
+            fprintf(stderr, "%s: error: chunk size (%zu) exceeds batch size (%zu), increase batch size and re-run\n",__func__, inp.size(), n_batch);
+            return 1;
         }
         // add eos if not present
         if (inp.empty() || inp.back() != llama_token_eos(model)) {