increases the max number of threads

Author: taku910

Diff for: src/trainer_interface.cc

@@ -67,7 +67,7 @@ util::Status VerifySpec(const TrainerSpec &trainer_spec) {
   CHECK_RANGE(trainer_spec.character_coverage(), 0.98, 1.0);
   CHECK_RANGE(trainer_spec.max_sentencepiece_length(), 1, 512);
   CHECK_RANGE(trainer_spec.num_sub_iterations(), 1, 10);
-  CHECK_RANGE(trainer_spec.num_threads(), 1, 128);
+  CHECK_RANGE(trainer_spec.num_threads(), 1, 1024);
   CHECK_RANGE(trainer_spec.self_test_sample_size(), 0, 1000);
   CHECK_RANGE(trainer_spec.shrinking_factor(), 0.5, 0.95);
   CHECK_RANGE(trainer_spec.max_sentence_length(), 10, 1073741824);