From 7eb02f17621af790a6afb4bf0f94a7452923206f Mon Sep 17 00:00:00 2001
From: FengZiYjun <writerphone@163.com>
Date: Fri, 11 Jan 2019 20:59:42 +0800
Subject: [PATCH] update code comments in CRF

---
 fastNLP/modules/aggregator/attention.py |  6 ++++--
 fastNLP/modules/decoder/CRF.py          | 26 +++++++++++++------------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/fastNLP/modules/aggregator/attention.py b/fastNLP/modules/aggregator/attention.py
index a26b195d..3fea1b10 100644
--- a/fastNLP/modules/aggregator/attention.py
+++ b/fastNLP/modules/aggregator/attention.py
@@ -1,7 +1,9 @@
+import math
+
 import torch
-from torch import nn
 import torch.nn.functional as F
-import math
+from torch import nn
+
 from fastNLP.modules.utils import mask_softmax
 
 
diff --git a/fastNLP/modules/decoder/CRF.py b/fastNLP/modules/decoder/CRF.py
index fe7a8465..d7db3bf9 100644
--- a/fastNLP/modules/decoder/CRF.py
+++ b/fastNLP/modules/decoder/CRF.py
@@ -19,13 +19,14 @@ def seq_len_to_byte_mask(seq_lens):
     mask = broadcast_arange.float().lt(seq_lens.float().view(-1, 1))
     return mask
 
+
 def allowed_transitions(id2label, encoding_type='bio'):
     """
 
-    :param id2label: dict, key是label的indices，value是str类型的tag或tag-label。value可以是只有tag的, 比如"B", "M"; 也可以是
+    :param dict id2label: key是label的indices，value是str类型的tag或tag-label。value可以是只有tag的, 比如"B", "M"; 也可以是
         "B-NN", "M-NN", tag和label之间一定要用"-"隔开。一般可以通过Vocabulary.get_id2word()id2label。
     :param encoding_type: str, 支持"bio", "bmes"。
-    :return:List[Tuple(int, int)]], 内部的Tuple是(from_tag_id, to_tag_id)。 返回的结果考虑了start和end，比如"BIO"中，B、O可以
+    :return: List[Tuple(int, int)]], 内部的Tuple是(from_tag_id, to_tag_id)。 返回的结果考虑了start和end，比如"BIO"中，B、O可以
         位于序列的开端，而I不行。所以返回的结果中会包含(start_idx, B_idx), (start_idx, O_idx), 但是不包含(start_idx, I_idx).
         start_idx=len(id2label), end_idx=len(id2label)+1。
     """
@@ -57,6 +58,7 @@ def allowed_transitions(id2label, encoding_type='bio'):
                 allowed_trans.append((from_id, to_id))
     return allowed_trans
 
+
 def is_transition_allowed(encoding_type, from_tag, from_label, to_tag, to_label):
     """
 
@@ -130,16 +132,16 @@ def is_transition_allowed(encoding_type, from_tag, from_label, to_tag, to_label)
 
 
 class ConditionalRandomField(nn.Module):
-    def __init__(self, num_tags, include_start_end_trans=False, allowed_transitions=None, initial_method=None):
-        """
+    """
 
-        :param num_tags: int, 标签的数量。
-        :param include_start_end_trans: bool, 是否包含起始tag
-        :param allowed_transitions: List[Tuple[from_tag_id(int), to_tag_id(int)]]. 允许的跃迁，可以通过allowed_transitions()得到。
-            如果为None，则所有跃迁均为合法
-        :param initial_method:
-        """
+    :param int num_tags: 标签的数量。
+    :param bool include_start_end_trans: 是否包含起始tag
+    :param list allowed_transitions: ``List[Tuple[from_tag_id(int), to_tag_id(int)]]``. 允许的跃迁，可以通过allowed_transitions()得到。
+        如果为None，则所有跃迁均为合法
+    :param str initial_method:
+    """
 
+    def __init__(self, num_tags, include_start_end_trans=False, allowed_transitions=None, initial_method=None):
         super(ConditionalRandomField, self).__init__()
 
         self.include_start_end_trans = include_start_end_trans
@@ -235,8 +237,8 @@ class ConditionalRandomField(nn.Module):
         return all_path_score - gold_path_score
 
     def viterbi_decode(self, data, mask, get_score=False, unpad=False):
-        """
-        Given a feats matrix, return best decode path and best score.
+        """Given a feats matrix, return best decode path and best score.
+
         :param data:FloatTensor, batch_size x max_len x num_tags
         :param mask:ByteTensor batch_size x max_len
         :param get_score: bool, whether to output the decode score.