diff --git a/infer-web.py b/infer-web.py
index b027f0e..a4a2c29 100644
--- a/infer-web.py
+++ b/infer-web.py
@@ -72,7 +72,7 @@ from config import (
     noautoopen,
 )
 from infer_uvr5 import _audio_pre_
-from my_utils import load_audio
+from my_utils import load_audio, train_index
 from train.process_ckpt import show_info, change_info, merge, extract_small_model
 
 # from trainset_preprocess_pipeline import PreProcess
@@ -614,47 +614,6 @@ def click_train(
     return "训练结束, 您可查看控制台训练日志或实验文件夹下的train.log"
 
 
-# but4.click(train_index, [exp_dir1], info3)
-def train_index(exp_dir1):
-    exp_dir = "%s/logs/%s" % (now_dir, exp_dir1)
-    os.makedirs(exp_dir, exist_ok=True)
-    feature_dir = "%s/3_feature256" % (exp_dir)
-    if os.path.exists(feature_dir) == False:
-        return "请先进行特征提取!"
-    listdir_res = list(os.listdir(feature_dir))
-    if len(listdir_res) == 0:
-        return "请先进行特征提取！"
-    npys = []
-    for name in sorted(listdir_res):
-        phone = np.load("%s/%s" % (feature_dir, name))
-        npys.append(phone)
-    big_npy = np.concatenate(npys, 0)
-    np.save("%s/total_fea.npy" % exp_dir, big_npy)
-    n_ivf = big_npy.shape[0] // 39
-    infos = []
-    infos.append("%s,%s" % (big_npy.shape, n_ivf))
-    yield "\n".join(infos)
-    index = faiss.index_factory(256, "IVF%s,Flat" % n_ivf)
-    infos.append("training")
-    yield "\n".join(infos)
-    index_ivf = faiss.extract_index_ivf(index)  #
-    index_ivf.nprobe = int(np.power(n_ivf, 0.3))
-    index.train(big_npy)
-    faiss.write_index(
-        index,
-        "%s/trained_IVF%s_Flat_nprobe_%s.index" % (exp_dir, n_ivf, index_ivf.nprobe),
-    )
-    infos.append("adding")
-    yield "\n".join(infos)
-    index.add(big_npy)
-    faiss.write_index(
-        index,
-        "%s/added_IVF%s_Flat_nprobe_%s.index" % (exp_dir, n_ivf, index_ivf.nprobe),
-    )
-    infos.append("成功构建索引, added_IVF%s_Flat_nprobe_%s.index" % (n_ivf, index_ivf.nprobe))
-    yield "\n".join(infos)
-
-
 # but5.click(train1key, [exp_dir1, sr2, if_f0_3, trainset_dir4, spk_id5, gpus6, np7, f0method8, save_epoch10, total_epoch11, batch_size12, if_save_latest13, pretrained_G14, pretrained_D15, gpus16, if_cache_gpu17], info3)
 def train1key(
     exp_dir1,
@@ -835,34 +794,7 @@ def train1key(
     p.wait()
     yield get_info_str("训练结束, 您可查看控制台训练日志或实验文件夹下的train.log")
     #######step3b:训练索引
-    feature_dir = "%s/3_feature256" % (exp_dir)
-    npys = []
-    listdir_res = list(os.listdir(feature_dir))
-    for name in sorted(listdir_res):
-        phone = np.load("%s/%s" % (feature_dir, name))
-        npys.append(phone)
-    big_npy = np.concatenate(npys, 0)
-    np.save("%s/total_fea.npy" % exp_dir, big_npy)
-    n_ivf = big_npy.shape[0] // 39
-    yield get_info_str("%s,%s" % (big_npy.shape, n_ivf))
-    index = faiss.index_factory(256, "IVF%s,Flat" % n_ivf)
-    yield get_info_str("training index")
-    index_ivf = faiss.extract_index_ivf(index)  #
-    index_ivf.nprobe = int(np.power(n_ivf, 0.3))
-    index.train(big_npy)
-    faiss.write_index(
-        index,
-        "%s/trained_IVF%s_Flat_nprobe_%s.index" % (exp_dir, n_ivf, index_ivf.nprobe),
-    )
-    yield get_info_str("adding index")
-    index.add(big_npy)
-    faiss.write_index(
-        index,
-        "%s/added_IVF%s_Flat_nprobe_%s.index" % (exp_dir, n_ivf, index_ivf.nprobe),
-    )
-    yield get_info_str(
-        "成功构建索引, added_IVF%s_Flat_nprobe_%s.index" % (n_ivf, index_ivf.nprobe)
-    )
+    yield from train_index(exp_dir1)
     yield get_info_str("全流程结束！")
 
 
diff --git a/my_utils.py b/my_utils.py
index 89a1527..c74776e 100644
--- a/my_utils.py
+++ b/my_utils.py
@@ -1,7 +1,71 @@
+import os
+
+import faiss
 import ffmpeg
 import numpy as np
 
 
+def train_index(exp_dir1):
+    '''train and save faiss index
+    
+    Args:
+        exp_dir1(string): Relative path where index is stored
+    '''
+    exp_dir = "%s/logs/%s" % (os.getcwd(), exp_dir1)
+    os.makedirs(exp_dir, exist_ok=True)
+    feature_dir = "%s/3_feature256" % (exp_dir)
+
+    if os.path.exists(feature_dir) == False:
+        return "请先进行特征提取!"
+    listdir_res = list(os.listdir(feature_dir))
+    if len(listdir_res) == 0:
+        return "请先进行特征提取！"
+
+    npys = []
+    for name in sorted(listdir_res):
+        phone = np.load("%s/%s" % (feature_dir, name))
+        npys.append(phone)
+    big_npy = np.concatenate(npys, 0)
+    np.save("%s/total_fea.npy" % exp_dir, big_npy)
+
+    # use recommended parameter in https://github.com/facebookresearch/faiss/wiki/Guidelines-to-choose-an-index
+    N = big_npy.shape[0]
+    dim = big_npy.shape[1]
+    if 4 * np.rint(np.sqrt(N)) * 30 > N:
+        n_ivf = N // 30
+    else:
+        n_ivf = -(-N // 256)
+        for x in range(4, 18, 2):
+            K = x * np.rint(np.sqrt(N)).astype(int)
+            if 30 * K <= N <= 256 * K:
+                n_ivf = K
+                break
+    index_string = "IVF%s,PQ%sx4fs,RFlat" % (n_ivf, -(-dim//2))
+    index_name = index_string.replace(",", "_")
+
+    
+    infos = []
+    infos.append("%s,%s" % (big_npy.shape, n_ivf))
+    yield "\n".join(infos)
+    index = faiss.index_factory(dim, index_string)
+    infos.append("training")
+    yield "\n".join(infos)
+    index.train(big_npy)
+    faiss.write_index(
+        index,
+        "%s/trained_%s.index" % (exp_dir, index_name),
+    )
+    infos.append("adding")
+    yield "\n".join(infos)
+    index.add(big_npy)
+    faiss.write_index(
+        index,
+        "%s/added_%s.index" % (exp_dir, index_name),
+    )
+    infos.append("成功构建索引, added_%s.index" % (index_name))
+    yield "\n".join(infos)
+
+
 def load_audio(file, sr):
     try:
         # https://github.com/openai/whisper/blob/main/whisper/audio.py#L26