cosine_sim=pairwise_distances(tfidf_matrix,metric="cosine")是什么意思

import pandas as pd from numpy import * food=pd.read_csv('hot-spicy pot.csv') food.head(10) food['taste'].head(5) import pandas as pd from numpy import * from sklearn.feature_extraction.text import TfidfVectorizer #1.读取数据 print('Step1:read data...') food=pd.read_csv('hot-spicy pot.csv') food.head(10) #2.将菜品的描述构造成TF-IDF向量 print('Step2:make TF-IDF...') tfidf=TfidfVectorizer(stop_words='english') tfidf_matrix=tfidf.fit_transform(food['taste']) tfidf_matrix.shape #3.计算两个菜品的余弦相似度 print('Step3:compute similarity...') from sklearn.metrics.pairwise import pairwise_distances cosine_sim=pairwise_distances(tfidf_matrix,metric="cosine") #推荐函数，输出与其最相似的10个菜品 def content_based_recommendation(name,consine_sim=cosine_sim): idx=indices[name] sim_scores=list(enumerate(cosine_sim[idx])) sim_scores=sorted(sim_scores,key=lambda x:x[1]) sim_scores=sim_scores[1:11] food_indices=[i[0]for i in sim_scores] return food['name'].iloc[food_indices] #4.根据菜名及特点进行推荐 print('Step4:recommend by name...') #建立索引，方便使用菜名进行数据访问 indices=pd.Series(food.index,index=food['name']).drop_duplicates() result=content_based_recommendation("celery") print(result)

这段代码是使用基于内容的推荐算法对热辣火锅菜品进行推荐。首先，读取了一个名为 'hot-spicy pot.csv' 的数据文件，然后将菜品的描述构造成TF-IDF向量，并计算了两个菜品的余弦相似度。接着，定义了一个推荐函数 ...

import pandas as pd from numpy import * movies=pd.io.parsers.read_csv('F:\python练习/1movie_metadata.csv') movies.head() movies['genres'].head() from sklearn.feature_extraction.text import TfidfVectorizer tfidf=TfidfVectorizer(stop_words='english') movies['genres']=movies['genres'].fillna('') tfidf_matrix=tfidf.fit_transform(movies['genres']) tfidf_matrix.shape from sklearn.metrics.pairwise import linear_kernel cosine_sim=linear_kernel(tfidf_matrix,tfidf_matrix) indices=pd.Series(movies.index,index=movies['movie_title']).drop_duplicates() def get_recommendation(title,consine_sim=cosine_sim): idx=indices[title] sim_scores=list(enumerate(cosine_sim[idx])) sim_scores=sorted(sim_scores,key=lambda x:x[1],reverse=True) sim_scores=sim_scores[1:11] movie_indices=[i[0]for i in sim_scores] return print(movies['movie_title'].iloc[movie_indices]) get_recommendation('Avatar?') 几个参数

3. cosine_sim=linear_kernel(tfidf_matrix,tfidf_matrix)：计算两个向量之间的余弦相似度，其中tfidf_matrix是通过TfidfVectorizer生成的特征矩阵。 4. sim_scores=sim_scores[1:11]：选择与输入电影最相似的...

def content_based_recommendation(name,consine_sim=cosine_sim): idx=indices[name] sim_scores=list(enumerate(cosine_sim[idx])) sim_scores=sorted(sim_scores,key=lambda x:x[1]) sim_scores=sim_scores[1:11] food_indices=[i[0]for i in sim_scores] return food['name'].iloc[food_indices]

这是一个基于内容的推荐算法，输入参数为食物名称和余弦相似度矩阵（默认为cosine_sim）。该算法会根据输入的食物名称找到对应的索引idx，并计算该食物与其他所有食物的相似度，并将结果存储在列表sim_scores中。...

else: self.total_N = 1000 self.beta_0 = continuous_beta_0 self.beta_1 = continuous_beta_1 self.cosine_s = 0.008 self.cosine_beta_max = 999. self.cosine_t_max = math.atan(self.cosine_beta_max * (1. + self.cosine_s) / math.pi) * 2. * (1. + self.cosine_s) / math.pi - self.cosine_s self.cosine_log_alpha_0 = math.log(math.cos(self.cosine_s / (1. + self.cosine_s) * math.pi / 2.)) self.schedule = schedule if schedule == 'cosine': # For the cosine schedule, T = 1 will have numerical issues. So we manually set the ending time T. # Note that T = 0.9946 may be not the optimal setting. However, we find it works well. self.T = 0.9946 else: self.T = 1.解析

其中包括总迭代次数、beta_0、beta_1、cosine_s、cosine_beta_max、cosine_t_max、cosine_log_alpha_0、schedule和T等属性。如果schedule属性的值是'cosine'，则设定T属性为0.9946，否则设为1。这段代码的目的是为了...

改写这段编码：cosine_similarities = cosine_similarity(df) print(cosine_similarities) from sklearn.cluster import KMeans kms = KMeans(n_clusters=10, random_state=123) k_data = kms.fit_predict(cosine_similarities) # 对余弦相似度的计算结果进行聚类分群 print(k_data) print(k_data == 3) print(words[0:3]) words_ary = np.array(words) print(words_ary[0:3])

from sklearn.metrics.pairwise import cosine_similarity cosine_similarities = cosine_similarity(df) print(cosine_similarities) # 对余弦相似度的计算结果进行聚类分群 from sklearn.cluster import KMeans ...

data = ["This two-wheeler is really good on slippery roads"] sentce=["This is really good"] from sklearn.feature_extraction.text import CountVectorizer from sklearn.feature_extraction.text import TfidfTransformer from sklearn.metrics.pairwise import cosine_similarity vectorizer = CountVectorizer() X_train_termcounts = vectorizer.fit_transform(data) tfidf_transformer = TfidfTransformer() X_train_tfidf = tfidf_transformer.fit_transform(X_train_termcounts) print ("\nTfidf of training data:", X_train_tfidf.toarray()) X_input_termcounts = vectorizer.transform(sentce) X_input_tfidf = tfidf_transformer.transform(X_input_termcounts) print ("\nTfidf of training data:", X_input_tfidf.toarray()) print("\nCosine of data:",cosine_similarity(X_train_tfidf,X_input_tfidf))代码注释

from sklearn.metrics.pairwise import cosine_similarity # 导入余弦相似度计算库 vectorizer = CountVectorizer() # 创建词袋模型 X_train_termcounts = vectorizer.fit_transform(data) # 对训练数据进行特征...

优化这款代码def compare(): text1 = text_new text2 = text_old tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform([text1, text2]) cosine_similarities = cosine_similarity(tf_idf_vectors) return cosine_similarities[0, 1]增加逐一对比功能

from sklearn.metrics.pairwise import cosine_similarity def compare(text_list): tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform(text_list) n = len(text_list) ...

# 3. Construct solver. lr = CustomWarmupCosineDecay(warmup_start_lr=warmup_start_lr, warmup_epochs=warmup_epochs, cosine_base_lr=cosine_base_lr, max_epoch=max_epoch, num_iters=1)

- 定义一个自定义的学习率调度器，其参数包括：学习率的初始值（warmup_start_lr）、预热期的epoch数（warmup_epochs）、余弦退火策略中的基础学习率（cosine_base_lr）、训练的最大epoch数（max_epoch）和每个epoch...

# lr max_epoch = 30 warmup_epochs = 5 warmup_start_lr = 0.0005 cosine_base_lr = 0.001 iter_step = True

- 从第6轮开始使用余弦退火学习率（cosine annealing learning rate）策略，学习率的值在0.0005到0.001之间变化； - 每次迭代时更新学习率（iterative learning rate）。需要注意的是，这些超参数的选择可能会因...

import torch from transformers import BertTokenizer, BertModel # 加载Bert预训练模型和tokenizer model = BertModel.from_pretrained('bert-base-chinese') tokenizer = BertTokenizer.from_pretrained('bert-base-chinese') # 微博文本和种子词 text = '今天天气真好，心情非常愉快！' seeds = ['天气', '心情', '愉快'] # 将微博文本和种子词转换为Bert输入格式 inputs = tokenizer.encode_plus(text, add_special_tokens=True, return_tensors='pt') seed_inputs = tokenizer.encode_plus(seeds, add_special_tokens=True, return_tensors='pt', padding=True) # 使用Bert模型获取微博文本和种子词的词向量 with torch.no_grad(): text_embeddings = model(inputs['input_ids'], attention_mask=inputs['attention_mask'])[0] # [1, seq_len, hidden_size] seed_embeddings = model(seed_inputs['input_ids'], attention_mask=seed_inputs['attention_mask'])[0] # [batch_size, seq_len, hidden_size] # 计算种子词和微博文本中所有词语的余弦相似度 text_embeddings = text_embeddings.squeeze(0) # [seq_len, hidden_size] seed_embeddings = seed_embeddings.mean(dim=1) # [batch_size, hidden_size] -> [batch_size, 1, hidden_size] -> [batch_size, hidden_size] cosine_similarities = torch.matmul(text_embeddings, seed_embeddings.transpose(0, 1)) # [seq_len, batch_size] # 获取相似度最高的词语 similar_words = [] for i in range(len(seeds)): seed_similarities = cosine_similarities[:, i].tolist() max_sim_idx = seed_similarities.index(max(seed_similarities)) similar_word = tokenizer.convert_ids_to_tokens(inputs['input_ids'][0][max_sim_idx].item()) similar_words.append(similar_word) print(similar_words) 能不能详细讲解一下上述这段代码的每行代码的意思，为什么这样用，比如用到的函数是什么意思，生成的变量是什么类型，能列举吗？而且这段代码中后面的这行代码seed_similarities = cosine_similarities[:, i].tolist()报错了，报错显示Traceback (most recent call last): File "E:/PyCharm Community Edition 2020.2.2/Project/WordDict/cos_similarity.py", line 35, in <module> seed_similarities = cosine_similarities[:, i].tolist() IndexError: index 1 is out of bounds for dimension 1 with size 1 能不能帮我解释一下为什么错，解释一下该怎么修改，并给出修改后的代码呢？

修改后的代码将cosine_similarities矩阵的维度调整为[seq_len, batch_size]，同时在for循环中将seed_similarities矩阵的第一个维度作为行索引，第二个维度作为列索引来获取余弦相似度。

import torch from transformers import BertTokenizer, BertModel # 加载Bert预训练模型和tokenizer model = BertModel.from_pretrained('bert-base-chinese') tokenizer = BertTokenizer.from_pretrained('bert-base-chinese') # 微博文本和种子词 text = '今天天气真好，心情非常愉快！' seeds = ['天气', '心情', '愉快'] # 将微博文本和种子词转换为Bert输入格式 inputs = tokenizer.encode_plus(text, add_special_tokens=True, return_tensors='pt') seed_inputs = tokenizer.encode_plus(seeds, add_special_tokens=True, return_tensors='pt', padding=True) # 使用Bert模型获取微博文本和种子词的词向量 with torch.no_grad(): text_embeddings = model(inputs['input_ids'], attention_mask=inputs['attention_mask'])[0] # [1, seq_len, hidden_size] seed_embeddings = model(seed_inputs['input_ids'], attention_mask=seed_inputs['attention_mask'])[0] # [batch_size, seq_len, hidden_size] # 计算种子词和微博文本中所有词语的余弦相似度 text_embeddings = text_embeddings.squeeze(0) # [seq_len, hidden_size] seed_embeddings = seed_embeddings.mean(dim=1) # [batch_size, hidden_size] -> [batch_size, 1, hidden_size] -> [batch_size, hidden_size] cosine_similarities = torch.matmul(text_embeddings, seed_embeddings.transpose(0, 1)) # [seq_len, batch_size] # 获取相似度最高的词语 similar_words = [] for i in range(len(seeds)): seed_similarities = cosine_similarities[:, i].tolist() max_sim_idx = seed_similarities.index(max(seed_similarities)) similar_word = tokenizer.convert_ids_to_tokens(inputs['input_ids'][0][max_sim_idx].item()) similar_words.append(similar_word) print(similar_words)

similar_word = tokenizer.convert_ids_to_tokens(inputs['input_ids'][0][max_sim_idx].item()) similar_words.append(similar_word) 7. 输出最相似的词语： print(similar_words) 该代码可以用于...

为什么这段代码def compare(text1, text2): similarities = [] text1 = ("text_new:\n", text_new) text2 = ("text_old:\n", text_old) for i in range(len(text1)): for j in range(len(text2)): tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform([text1[i], text2[j]]) cosine_similarities = cosine_similarity(tf_idf_vectors) similarities.append(cosine_similarities[0, 1]) print (similarities)结果不是逐一比较的结果？如何修改

cosine_similarities = cosine_similarity(tf_idf_vectors) similarities.append(cosine_similarities[0, 1]) print(similarities) 这样，text1 和 text2 中的文本将会一一对应地进行比较，从而得到正确...

优化这段代码def compare(text1, text2): similarities = [] text1 = ("text_new:\n", text_new) text2 = ("text_old:\n", text_old) for i in range(len(text1)): for j in range(len(text2)): tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform([text1[i], text2[j]]) cosine_similarities = cosine_similarity(tf_idf_vectors) similarities.append(cosine_similarities[0, 1]) print (similarities)实现text1逐次与text2中的字符串逐一比较

from sklearn.metrics.pairwise import cosine_similarity import itertools def compare(text1, text2): tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform([text1, ...

import torchfrom transformers import BertTokenizer, BertModel# 加载Bert预训练模型和tokenizermodel = BertModel.from_pretrained('bert-base-chinese')tokenizer = BertTokenizer.from_pretrained('bert-base-chinese')# 微博文本和种子词text = '今天天气真好，心情非常愉快！'seeds = ['天气', '心情', '愉快']# 将微博文本和种子词转换为Bert输入格式inputs = tokenizer.encode_plus(text, add_special_tokens=True, return_tensors='pt')seed_inputs = tokenizer.encode_plus(seeds, add_special_tokens=True, return_tensors='pt', padding=True)# 使用Bert模型获取微博文本和种子词的词向量with torch.no_grad(): text_embeddings = model(inputs['input_ids'], attention_mask=inputs['attention_mask'])[0] # [1, seq_len, hidden_size] seed_embeddings = model(seed_inputs['input_ids'], attention_mask=seed_inputs['attention_mask'])[0] # [batch_size, seq_len, hidden_size]# 计算种子词和微博文本中所有词语的余弦相似度text_embeddings = text_embeddings.squeeze(0) # [seq_len, hidden_size]seed_embeddings = seed_embeddings.mean(dim=1) # [batch_size, seq_len, hidden_size] -> [batch_size, hidden_size]cosine_similarities = torch.matmul(text_embeddings, seed_embeddings.transpose(0, 1)) # [seq_len, batch_size]# 获取相似度最高的词语similar_words = []for i in range(len(seeds)): seed_similarities = cosine_similarities[i, :].tolist() max_sim_idx = seed_similarities.index(max(seed_similarities)) similar_word = tokenizer.convert_ids_to_tokens(inputs['input_ids'][0][max_sim_idx].item()) similar_words.append(similar_word)print(similar_words) 上述修改后的代码输出全是['[CLS]', '[CLS]', '[CLS]']，这不是我想要的结果啊，我想要的是微博文本的词语和种子词很相似的所有词语，而不是bert自动添加的特殊标记符，该怎么办

cosine_similarities = torch.matmul(text_embeddings, seed_embeddings.transpose(0, 1)) # [seq_len, batch_size] # 获取相似度最高的词语 similar_words = [] for i in range(len(seeds)): seed_similarities =...

cosine_loss = 1 - cos_similarity为什么余弦损失是等于1-余弦损失度

余弦相似度（cosine similarity）是用来衡量两个向量之间的相似性的度量方法。它的取值范围在[-1, 1]之间，其中1表示完全相似，-1表示完全不相似。当我们使用余弦相似度来进行相似性度量时，通常会将其转化为余弦...

cosine_sim=pairwise_distances(tfidf_matrix,metric="cosine")是什么意思

cosine_sim=pairwise_distances(tfidf_matrix,metric="cosine")

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def content_based_recommendation(name,consine_sim=cosine_sim): idx=indices[name] sim_scores=list(enumerate(cosine_sim[idx])) sim_scores=sorted(sim_scores,key=lambda x:x[1]) sim_scores=sim_scores[1:11] food_indices=[i[0]for i in sim_scores] return food['name'].iloc[food_indices]

优化这款代码def compare(): text1 = text_new text2 = text_old tf_idf_vectorizer = TfidfVectorizer() tf_idf_vectors = tf_idf_vectorizer.fit_transform([text1, text2]) cosine_similarities = cosine_similarity(tf_idf_vectors) return cosine_similarities[0, 1]增加逐一对比功能

# 3. Construct solver. lr = CustomWarmupCosineDecay(warmup_start_lr=warmup_start_lr, warmup_epochs=warmup_epochs, cosine_base_lr=cosine_base_lr, max_epoch=max_epoch, num_iters=1)

# lr max_epoch = 30 warmup_epochs = 5 warmup_start_lr = 0.0005 cosine_base_lr = 0.001 iter_step = True

cosine_loss = 1 - cos_similarity为什么余弦损失是等于1-余弦损失度

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