Python torch.multinomial函数代码示例

 def sample(self,batch_size,seq_len,data=None):
     #用来采样出一个batch的结果，
     """
     data 是已有序列
     """
     #如果没有data就从０开始
     if data is None:
         sample_batch=(torch.zeros(batch_size,seq_len).type(torch.LongTensor)).cuda()
         inp=Variable(torch.zeros(batch_size,1).type(torch.LongTensor)).cuda()
         h=self.init_hidden(batch_size)
         for i in range(seq_len):
             output,h=self.forward(inp,h)
             output=torch.multinomial(output.exp().squeeze(),1)
             sample_batch[:,i]=output.data
             inp=output
         return sample＿batch
     #否则就从部分开始
     else:
         sample_batch=(torch.zeros(batch_size,seq_len).type(torch.LongTensor)).cuda()
         inp=Variable(torch.zeros(batch_size,1).type(torch.LongTensor)).cuda()
         h=self.init_hidden(batch_size)
         for i in range(seq_len):
             if i<data.size(1):
                 inp=data[:,i].unsqueeze(1)
             else:
                 inp=sample_batch[:,i-1].unsqueeze(1)
             output,h=self.forward(inp,h)
             output=torch.multinomial(output.exp().squeeze(),1)
             sample_batch[:,i]=output.data
         return sample＿batch

def blue_eval(output,corpus):
    #采样以后为２０＊１９
    sent_idx=torch.multinomial(output.exp().cpu(), 1).view(-1,19)
    sent_idx=sent_idx.cpu().data.numpy()
    sent_str=[]

    #对生产的一个batch量数据进行处理
    for i in range(sent_idx.shape[0]):
        str_=[str(int(x)) for x in sent_idx[i,:-1]]
        sent_str.append(str_)

    eval_data=[]
    for sent in corpus.valid.numpy():
        eval_data.append([str(int(x)) for x in sent[1:-1]])

    weight = tuple((1. / 4 for _ in range(4)))
    BLEUscores=[]

    for gen_sent in sent_str:
        ref_sent_info=[]
        for ref_sent in eval_data:
            #找到与这个最相似的句子
            common_tokens = Counter(gen_sent) & Counter(ref_sent)
            correct_preds = sum(common_tokens.values())
            recall_wrt = float(correct_preds) / len(gen_sent)
            ref_sent_info.append((ref_sent,recall_wrt))

        ref_sent_info.sort(key=lambda x: -x[1])
        top_refs=[x[0] for x in ref_sent_info[:50]]

        BLEUscore = nltk.translate.bleu_score.sentence_bleu(top_refs, gen_sent, weight)
        BLEUscores.append(BLEUscore)

    score=(np.mean(BLEUscores))
    return score

    def forward(self, fc_feats, att_feats, seq):
        batch_size = fc_feats.size(0)
        state = self.init_hidden(batch_size)
        outputs = []

        for i in range(seq.size(1)):
            if i == 0:
                xt = self.img_embed(fc_feats)
            else:
                if self.training and i >= 2 and self.ss_prob > 0.0: # otherwiste no need to sample
                    sample_prob = fc_feats.data.new(batch_size).uniform_(0, 1)
                    sample_mask = sample_prob < self.ss_prob
                    if sample_mask.sum() == 0:
                        it = seq[:, i-1].clone()
                    else:
                        sample_ind = sample_mask.nonzero().view(-1)
                        it = seq[:, i-1].data.clone()
                        #prob_prev = torch.exp(outputs[-1].data.index_select(0, sample_ind)) # fetch prev distribution: shape Nx(M+1)
                        #it.index_copy_(0, sample_ind, torch.multinomial(prob_prev, 1).view(-1))
                        prob_prev = torch.exp(outputs[-1].data) # fetch prev distribution: shape Nx(M+1)
                        it.index_copy_(0, sample_ind, torch.multinomial(prob_prev, 1).view(-1).index_select(0, sample_ind))
                        it = Variable(it, requires_grad=False)
                else:
                    it = seq[:, i-1].clone()
                # break if all the sequences end
                if i >= 2 and seq[:, i-1].data.sum() == 0:
                    break
                xt = self.embed(it)

            output, state = self.core(xt, state)
            output = F.log_softmax(self.logit(output))
            outputs.append(output)

        return torch.cat([_.unsqueeze(1) for _ in outputs[1:]], 1).contiguous()

def predict_fn(input_data, model):
    logger.info('Generating text based on input parameters.')
    corpus = model['corpus']
    model = model['model']

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    logger.info('Current device: {}'.format(device))
    torch.manual_seed(input_data['seed'])
    ntokens = len(corpus.dictionary)
    input = torch.randint(ntokens, (1, 1), dtype=torch.long).to(device)
    hidden = model.init_hidden(1)

    logger.info('Generating {} words.'.format(input_data['words']))
    result = []
    with torch.no_grad():  # no tracking history
        for i in range(input_data['words']):
            output, hidden = model(input, hidden)
            word_weights = output.squeeze().div(input_data['temperature']).exp().cpu()
            word_idx = torch.multinomial(word_weights, 1)[0]
            input.fill_(word_idx)
            word = corpus.dictionary.idx2word[word_idx]
            word = word if type(word) == str else word.decode()
            if word == '<eos>':
                word = '\n'
            elif i % 12 == 11:
                word = word + '\n'
            else:
                word = word + ' '
            result.append(word)
    return ''.join(result)

 def sample(self, sample_shape=torch.Size()):
     sample_shape = self._extended_shape(sample_shape)
     param_shape = sample_shape + torch.Size((self._num_events,))
     probs = self.probs.expand(param_shape)
     probs_2d = probs.contiguous().view(-1, self._num_events)
     sample_2d = torch.multinomial(probs_2d, 1, True)
     return sample_2d.contiguous().view(sample_shape)

def translate(enc_input='thisissungkim.iloveyou.', predict_len=100, temperature=0.9):
    input_var = str2tensor(enc_input)
    encoder_hidden = encoder.init_hidden()
    encoder_outputs, encoder_hidden = encoder(input_var, encoder_hidden)

    hidden = encoder_hidden

    predicted = ''
    dec_input = str2tensor(SOS_token)
    for c in range(predict_len):
        output, hidden = decoder(dec_input, hidden)

        # Sample from the network as a multi nominal distribution
        output_dist = output.data.view(-1).div(temperature).exp()
        top_i = torch.multinomial(output_dist, 1)[0]

        # Stop at the EOS
        if top_i is EOS_token:
            break

        predicted_char = chr(top_i)
        predicted += predicted_char

        dec_input = str2tensor(predicted_char)

    return enc_input, predicted

 def sample(self, input, temperature=1., hidden=None):
     hidden = self.module_.init_hidden(1) if hidden is None else hidden
     output, hidden = self.module_(input, hidden)
     probas = output.squeeze().data.div(temperature).exp()
     sample = torch.multinomial(probas, 1)[-1]
     if probas.dim() > 1:
         sample = sample[0]
     return sample, self.repackage_hidden(hidden)

def torch_multinomial(input, num_samples, replacement=False):
    """
    Like `torch.multinomial()` but works with cuda tensors.
    Does not support keyword argument `out`.
    """
    if input.is_cuda:
        return torch_multinomial(input.cpu(), num_samples, replacement).cuda()
    else:
        return torch.multinomial(input, num_samples, replacement)

    def sample(self, fc_feats, att_feats, opt={}):
        sample_max = opt.get('sample_max', 1)
        beam_size = opt.get('beam_size', 1)
        temperature = opt.get('temperature', 1.0)
        if beam_size > 1:
            return self.sample_beam(fc_feats, att_feats, opt)

        batch_size = fc_feats.size(0)
        state = self.init_hidden(batch_size)

        # embed fc and att feats
        fc_feats = self.fc_embed(fc_feats)
        _att_feats = self.att_embed(att_feats.view(-1, self.att_feat_size))
        att_feats = _att_feats.view(*(att_feats.size()[:-1] + (self.rnn_size,)))

        # Project the attention feats first to reduce memory and computation comsumptions.
        p_att_feats = self.ctx2att(att_feats.view(-1, self.rnn_size))
        p_att_feats = p_att_feats.view(*(att_feats.size()[:-1] + (self.att_hid_size,)))

        seq = []
        seqLogprobs = []
        for t in range(self.seq_length + 1):
            if t == 0: # input <bos>
                it = fc_feats.data.new(batch_size).long().zero_()
            elif sample_max:
                sampleLogprobs, it = torch.max(logprobs.data, 1)
                it = it.view(-1).long()
            else:
                if temperature == 1.0:
                    prob_prev = torch.exp(logprobs.data).cpu() # fetch prev distribution: shape Nx(M+1)
                else:
                    # scale logprobs by temperature
                    prob_prev = torch.exp(torch.div(logprobs.data, temperature)).cpu()
                it = torch.multinomial(prob_prev, 1).cuda()
                sampleLogprobs = logprobs.gather(1, Variable(it, requires_grad=False)) # gather the logprobs at sampled positions
                it = it.view(-1).long() # and flatten indices for downstream processing

            xt = self.embed(Variable(it, requires_grad=False))

            if t >= 1:
                # stop when all finished
                if t == 1:
                    unfinished = it > 0
                else:
                    unfinished = unfinished * (it > 0)
                if unfinished.sum() == 0:
                    break
                it = it * unfinished.type_as(it)
                seq.append(it) #seq[t] the input of t+2 time step

                seqLogprobs.append(sampleLogprobs.view(-1))

            output, state = self.core(xt, fc_feats, att_feats, p_att_feats, state)
            logprobs = F.log_softmax(self.logit(output))

        return torch.cat([_.unsqueeze(1) for _ in seq], 1), torch.cat([_.unsqueeze(1) for _ in seqLogprobs], 1)

    def forward(self, x, hiddens):
        batchsize = x["s"].size(0)
        if not hasattr(self, "prob"):
            self.prob = x["res"].clone().resize_(2)
            self.prob[0] = 1 - self.args.ratio_skip_observation
            self.prob[1] = self.args.ratio_skip_observation

        skip_mat = self._var(torch.multinomial(self.prob, batchsize, replacement=True).float().view(-1, 1))

        output = self._merge(x, hiddens, skip_mat)
        return self.decision(output)

def sample_K(probs, K, mode='test'):
    probs = 1e-6 + probs*(1 - 2e-6) # to avoid log(0)
    probs = probs.view(-1, 2**K)
    if mode == 'train':
        bin_sample = torch.multinomial(probs, 1).detach()
    else:
        bin_sample = probs.max(1)[1].detach().unsqueeze(1)
    sample = bin_sample.clone().type(dtype)
    log_probs_samples = torch.log(probs).gather(1, bin_sample).squeeze()
    log_probs_samples = log_probs_samples.view(batch_size, N).sum(1)
    return bin_sample.data.view(batch_size, N), log_probs_samples

 def sample(self, Q):
     if self.use_actor_critic:
         pi = F.softmax(Q, dim=-1)
         a = torch.multinomial(pi, 1).squeeze()
         return a.data.cpu().numpy()
     else:
         sample = random.random()
         if sample > self.eps_threshold:
             return Q.data.max(1)[1].cpu().numpy()
         else:
             return np.random.randint(0, self.num_actions, self.nenv)

def main():
    path='my_data1'
    sec_text="I wanna go out tonight"
    n_bins=4

    #加载数据，默认是data1
    corpus = data.Corpus(path=os.path.join("data", path))
    gen=torch.load("models/gen_"+path+".pt").cuda()
    print(gen)

    bin_stream=string2bins(sec_text,n_bins)

    ntokens = len(corpus.dictionary)
    tokens = list(range(ntokens)) # * args.replication_factor
    np.random.shuffle(tokens)
    words_in_bin = int(len(tokens) /n_bins)
    bins = [tokens[i:i + words_in_bin] for i in range(0, len(tokens), words_in_bin)]
    zero = [list(set(tokens) - set(bin_)) for bin_ in bins]



    #循环生成每一个词

    for _ in range(10):

        input = Variable(torch.Tensor([corpus.dictionary.word2idx['<start>']]), volatile=True).view(-1,1).type(torch.LongTensor).cuda()
        h=gen.init_hidden(1)
        gen_words=[]
        for i in range(len(bin_stream[:16])):
            output,h=gen(input,h)

            zero_index = zero[int(bin_stream[i],2)]
            zero_index = torch.LongTensor(zero_index).cuda()

            output = output.squeeze().data.div(0.8).exp()
            output.index_fill_(0, zero_index, 0)

            word_idx = torch.multinomial(output, 1)[0]
            gen_words.append(word_idx)
            input.data.fill_(word_idx)

        print(len(gen_words))
        str_=" ".join([corpus.dictionary.idx2word[x] for x in gen_words])
        print(str_)

    def sample(self, max_time_step=200):
        """generate one sample"""
        sample_words = [self.vocab['<s>']]
        h_tm1 = None
        for t in xrange(max_time_step):
            x_tm1_embed = self.embed(Variable(torch.LongTensor([sample_words[-1]])))
            x_tm1_embed = x_tm1_embed.unsqueeze(0)
            h_t, (last_state, last_cell) = self.lstm(x_tm1_embed, h_tm1)
            h_t = self.dropout(h_t.view(-1))
            p_t = F.softmax(self.read_out(h_t), dim=-1)
            x_t_wid = torch.multinomial(p_t).data[0]
            x_t = self.vocab.id2word[x_t_wid]

            if x_t == '</s>':
                return [self.vocab.id2word[wid] for wid in sample_words[1:]]
            else:
                sample_words.append(x_t_wid)

            h_tm1 = last_state, last_cell

def sample_from_model(model, vectorizer, nationalities, sample_size=20,
                      temperature=1.0):
    num_samples = len(nationalities)
    begin_seq_index = [vectorizer.char_vocab.begin_seq_index
                       for _ in range(num_samples)]
    begin_seq_index = torch.tensor(begin_seq_index, dtype=torch.int64).unsqueeze(dim=1)
    indices = [begin_seq_index]
    nationality_indices = torch.tensor(nationalities, dtype=torch.int64).unsqueeze(dim=0)
    h_t = model.nation_emb(nationality_indices)

    for time_step in range(sample_size):
        x_t = indices[time_step]
        x_emb_t = model.char_emb(x_t)
        rnn_out_t, h_t = model.rnn(x_emb_t, h_t)
        prediction_vector = model.fc(rnn_out_t.squeeze(dim=1))
        probability_vector = F.softmax(prediction_vector / temperature, dim=1)
        indices.append(torch.multinomial(probability_vector, num_samples=1))
    indices = torch.stack(indices).squeeze().permute(1, 0)
    return indices