fix multiprocessing bug

[leminhnguyen]

Hi @RayeRen, today I've tried your preprocess.py code for LJSpeech dataset. And I realized that there were some processed items in metadata.json doesn't have ph_token key or len(ph.split()) is not equal to len(ph_token). So I've checked your code and found the problem with the line 123 in utils/commons/multiprocess_utils.py.

NATSpeech/utils/commons/multiprocess_utils.py

Lines 120 to 125 in e7e68d6

	for job_i, res in manager.get_results():
	results[job_i] = res
	while i_now < n_jobs and (not isinstance(results[i_now], str) or results[i_now] != '<WAIT>'):
	yield job_i, results[i_now]
	results[i_now] = None
	i_now += 1

For my understanding, you tried to return the indices and results as passed order instead of processed order, so I think i_now should be yielded instead of job_i. I also code a small snippet to debug your code, you can use it as reference.

def test_map_func(idx):
    import time
    time.sleep(0.2)
    return {"number": idx*2, "id": idx}

if __name__ == "__main__":
    args = [{"idx": idx} for idx in range(100)]
    ids = []
    for idx, x in multiprocess_run_tqdm(test_map_func, args):
        # args[idx].update(x)
        ids.append(idx)
   print(ids) 
   # print [0, 1, 2, 3, 4, 5, 5, 7, 7, 7, 7, 7, ...] with yield job_i
   # print [0, 1, 2, 3, 4, 6, 7, 8, 9, 10, ...] with yield i_now