minor fix: repeat fp substitution

llm_src/utils/fp_substitution.py

@@ -29,8 +29,11 @@ def generate_fp_nums_multiarith(orig_nums, repeat_time):
     
     fp_repl_numbers_list = []
     num_repl = len(orig_nums)
+    idx_candis = [_ for _ in range(len(nums_candis))]
+    random.shuffle(idx_candis)
+
     for num_var in range(repeat_time):
-        idx_candi = random.randint(0, len(nums_candis) - 1)
+        idx_candi = idx_candis[num_var]
         num_pick = sorted(nums_candis[idx_candi])
         num_order = np.argsort(orig_nums).tolist()
         cur_rdx = 0