Python torch.tensor方法代码示例

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def forward(self, feats):
        """Forward features from the upstream network.

        Args:
            feats (tuple[Tensor]): Features from the upstream network, each is
                a 4D-tensor.

        Returns:
            tuple: Usually a tuple of classification scores and bbox prediction
                cls_scores (list[Tensor]): Classification and quality (IoU)
                    joint scores for all scale levels, each is a 4D-tensor,
                    the channel number is num_classes.
                bbox_preds (list[Tensor]): Box distribution logits for all
                    scale levels, each is a 4D-tensor, the channel number is
                    4*(n+1), n is max value of integral set.
        """
        return multi_apply(self.forward_single, feats, self.scales) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def forward(self, feats):
        """Forward features from the upstream network.

        Args:
            feats (tuple[Tensor]): Features from the upstream network, each is
                a 4D-tensor.

        Returns:
            tuple: Usually a tuple of classification scores and bbox prediction
                cls_scores (list[Tensor]): Classification scores for all scale
                    levels, each is a 4D-tensor, the channels number is
                    num_anchors * num_classes.
                bbox_preds (list[Tensor]): Box energies / deltas for all scale
                    levels, each is a 4D-tensor, the channels number is
                    num_anchors * 4.
        """
        return multi_apply(self.forward_single, feats, self.scales) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def generate_grid(num_grid, size, device):
    """Generate regular square grid of points in [0, 1] x [0, 1] coordinate
    space.

    Args:
        num_grid (int): The number of grids to sample, one for each region.
        size (tuple(int, int)): The side size of the regular grid.
        device (torch.device): Desired device of returned tensor.

    Returns:
        (torch.Tensor): A tensor of shape (num_grid, size[0]*size[1], 2) that
            contains coordinates for the regular grids.
    """

    affine_trans = torch.tensor([[[1., 0., 0.], [0., 1., 0.]]], device=device)
    grid = F.affine_grid(
        affine_trans, torch.Size((1, 1, *size)), align_corners=False)
    grid = normalize(grid)
    return grid.view(1, -1, 2).expand(num_grid, -1, -1) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def to_tensor(data):
    """Convert objects of various python types to :obj:`torch.Tensor`.

    Supported types are: :class:`numpy.ndarray`, :class:`torch.Tensor`,
    :class:`Sequence`, :class:`int` and :class:`float`.

    Args:
        data (torch.Tensor | numpy.ndarray | Sequence | int | float): Data to
            be converted.
    """

    if isinstance(data, torch.Tensor):
        return data
    elif isinstance(data, np.ndarray):
        return torch.from_numpy(data)
    elif isinstance(data, Sequence) and not mmcv.is_str(data):
        return torch.tensor(data)
    elif isinstance(data, int):
        return torch.LongTensor([data])
    elif isinstance(data, float):
        return torch.FloatTensor([data])
    else:
        raise TypeError(f'type {type(data)} cannot be converted to tensor.') 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def random_choice(gallery, num):
        """Randomly select some elements from the gallery.

        If `gallery` is a Tensor, the returned indices will be a Tensor;
        If `gallery` is a ndarray or list, the returned indices will be a
        ndarray.

        Args:
            gallery (Tensor | ndarray | list): indices pool.
            num (int): expected sample num.

        Returns:
            Tensor or ndarray: sampled indices.
        """
        assert len(gallery) >= num

        is_tensor = isinstance(gallery, torch.Tensor)
        if not is_tensor:
            gallery = torch.tensor(
                gallery, dtype=torch.long, device=torch.cuda.current_device())
        perm = torch.randperm(gallery.numel(), device=gallery.device)[:num]
        rand_inds = gallery[perm]
        if not is_tensor:
            rand_inds = rand_inds.cpu().numpy()
        return rand_inds 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def test_strides():
    from mmdet.core import AnchorGenerator
    # Square strides
    self = AnchorGenerator([10], [1.], [1.], [10])
    anchors = self.grid_anchors([(2, 2)], device='cpu')

    expected_anchors = torch.tensor([[-5., -5., 5., 5.], [5., -5., 15., 5.],
                                     [-5., 5., 5., 15.], [5., 5., 15., 15.]])

    assert torch.equal(anchors[0], expected_anchors)

    # Different strides in x and y direction
    self = AnchorGenerator([(10, 20)], [1.], [1.], [10])
    anchors = self.grid_anchors([(2, 2)], device='cpu')

    expected_anchors = torch.tensor([[-5., -5., 5., 5.], [5., -5., 15., 5.],
                                     [-5., 15., 5., 25.], [5., 15., 15., 25.]])

    assert torch.equal(anchors[0], expected_anchors) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def test_ce_loss():
    # use_mask and use_sigmoid cannot be true at the same time
    with pytest.raises(AssertionError):
        loss_cfg = dict(
            type='CrossEntropyLoss',
            use_mask=True,
            use_sigmoid=True,
            loss_weight=1.0)
        build_loss(loss_cfg)

    # test loss with class weights
    loss_cls_cfg = dict(
        type='CrossEntropyLoss',
        use_sigmoid=False,
        class_weight=[0.8, 0.2],
        loss_weight=1.0)
    loss_cls = build_loss(loss_cls_cfg)
    fake_pred = torch.Tensor([[100, -100]])
    fake_label = torch.Tensor([1]).long()
    assert torch.allclose(loss_cls(fake_pred, fake_label), torch.tensor(40.))

    loss_cls_cfg = dict(
        type='CrossEntropyLoss', use_sigmoid=False, loss_weight=1.0)
    loss_cls = build_loss(loss_cls_cfg)
    assert torch.allclose(loss_cls(fake_pred, fake_label), torch.tensor(200.)) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def collate_fn(queries, tokenizer, sample, max_seq_len=None):
    token_id_seqs = [[1] + tokenizer(x, **sample) + [2] for x in queries]

    length = [len(x) - 1 for x in token_id_seqs]
    if max_seq_len is None or max_seq_len > max(length) + 1:
        max_seq_len = max(length) + 1

    padded = []
    mask = []
    for x in token_id_seqs:
        x = x[:max_seq_len]
        pad_length = max_seq_len - len(x)
        padded.append(x + [0] * pad_length)
        mask.append([1] * (len(x) - 1) + [0] * pad_length)

    padded = torch.tensor(padded).t().contiguous()
    length = torch.tensor(length)
    mask = torch.tensor(mask).t().contiguous()
    return padded[:-1], padded[1:], length, mask 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def process_embedding(self, embedding,
                          residue_reduction=True, protein_reduction=False):
        '''
            Direct output of ELMo has shape (3,L,1024), with L being the protein's
            length, 3 being the number of layers used to train SeqVec (1 CharCNN, 2 LSTMs)
            and 1024 being a hyperparameter chosen to describe each amino acid.
            When a representation on residue level is required, you can sum
            over the first dimension, resulting in a tensor of size (L,1024).
            If you want to reduce each protein to a fixed-size vector, regardless of its
            length, you can average over dimension L.
        '''
        embedding = torch.tensor(embedding)
        if residue_reduction:
            embedding = embedding.sum(dim=0)
        elif protein_reduction:
            embedding = embedding.sum(dim=0).mean(dim=0)

        return embedding.cpu().detach().numpy() 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def get_params():
    def _one(shape):
        ts = torch.tensor(np.random.normal(0, 0.01, size=shape), device=device, dtype=torch.float32)
        return torch.nn.Parameter(ts, requires_grad=True)

    def _three():
        return (_one((num_inputs, num_hiddens)),
                _one((num_hiddens, num_hiddens)),
                torch.nn.Parameter(torch.zeros(num_hiddens, device=device, dtype=torch.float32), requires_grad=True))

    W_xz, W_hz, b_z = _three() # 更新门参数
    W_xr, W_hr, b_r = _three() # 重置门参数
    W_xh, W_hh, b_h = _three() # 候选隐藏层参数

    # 输出层参数
    W_hq = _one((num_hiddens, num_outputs))
    b_q = torch.nn.Parameter(torch.zeros(num_outputs, device=device, dtype=torch.float32), requires_grad=True)
    return nn.ParameterList([W_xz, W_hz, b_z, W_xr, W_hr, b_r, W_xh, W_hh, b_h, W_hq, b_q]) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def data_iter_random(corpus_indices, batch_size, num_steps, device=None):
    # 减1是因为输出的索引x是相应输入的索引y加1
    num_examples = (len(corpus_indices) - 1) // num_steps
    epoch_size = num_examples // batch_size
    example_indices = list(range(num_examples))
    random.shuffle(example_indices)

    # 返回从pos开始的长为num_steps的序列
    def _data(pos):
        return corpus_indices[pos: pos + num_steps]

    if device is None:
        device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

    for i in range(epoch_size):
        # 每次读取batch_size个随机样本
        i = i * batch_size
        batch_indices = example_indices[i: i + batch_size]
        X = [_data(j * num_steps) for j in batch_indices]
        Y = [_data(j * num_steps + 1) for j in batch_indices]
        yield torch.tensor(X, dtype=torch.float32, device=device), torch.tensor(Y, dtype=torch.float32, device=device) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def predict_rnn_pytorch(prefix, num_chars, model, vocab_size, device, idx_to_char,
                        char_to_idx):
    state = None
    output = [char_to_idx[prefix[0]]]  # output会记录prefix加上输出
    for t in range(num_chars + len(prefix) - 1):
        X = torch.tensor([output[-1]], device=device).view(1, 1)
        if state is not None:
            if isinstance(state, tuple):  # LSTM, state:(h, c)
                state = (state[0].to(device), state[1].to(device))
            else:
                state = state.to(device)

        (Y, state) = model(X, state)  # 前向计算不需要传入模型参数
        if t < len(prefix) - 1:
            output.append(char_to_idx[prefix[t + 1]])
        else:
            output.append(int(Y.argmax(dim=1).item()))
    return ''.join([idx_to_char[i] for i in output]) 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def generate_dataset(true_w, true_b):
    num_examples = 1000

    features = torch.tensor(np.random.normal(0, 1, (num_examples, num_inputs)), dtype=torch.float)
    # 真实 label
    labels = true_w[0] * features[:, 0] + true_w[1] * features[:, 1] + true_b
    # 添加噪声
    labels += torch.tensor(np.random.normal(0, 0.01, size=labels.size()), dtype=torch.float)
    # 展示下分布
    plt.scatter(features[:, 1].numpy(), labels.numpy(), 1)
    plt.show()
    
    return features, labels


# batch 读取数据集 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def batch_loss(encoder, decoder, X, Y, loss):
    batch_size = X.shape[0]
    enc_state = encoder.begin_state()
    enc_outputs, enc_state = encoder(X, enc_state)
    # 初始化解码器的隐藏状态
    dec_state = decoder.begin_state(enc_state)
    # 解码器在最初时间步的输入是BOS
    dec_input = torch.tensor([out_vocab.stoi[BOS]] * batch_size)
    # 我们将使用掩码变量mask来忽略掉标签为填充项PAD的损失
    mask, num_not_pad_tokens = torch.ones(batch_size,), 0
    l = torch.tensor([0.0])
    for y in Y.permute(1,0): # Y shape: (batch, seq_len)
        dec_output, dec_state = decoder(dec_input, dec_state, enc_outputs)
        l = l + (mask * loss(dec_output, y)).sum()
        dec_input = y  # 使用强制教学
        num_not_pad_tokens += mask.sum().item()
        # 将PAD对应位置的掩码设成0, 原文这里是 y != out_vocab.stoi[EOS], 感觉有误
        mask = mask * (y != out_vocab.stoi[PAD]).float()
    return l / num_not_pad_tokens 

# 需要导入模块: import torch [as 别名]
# 或者: from torch import tensor [as 别名]
def translate(encoder, decoder, input_seq, max_seq_len):
    in_tokens = input_seq.split(' ')
    in_tokens += [EOS] + [PAD] * (max_seq_len - len(in_tokens) - 1)
    enc_input = torch.tensor([[in_vocab.stoi[tk] for tk in in_tokens]]) # batch=1
    enc_state = encoder.begin_state()
    enc_output, enc_state = encoder(enc_input, enc_state)
    dec_input = torch.tensor([out_vocab.stoi[BOS]])
    dec_state = decoder.begin_state(enc_state)
    output_tokens = []
    for _ in range(max_seq_len):
        dec_output, dec_state = decoder(dec_input, dec_state, enc_output)
        pred = dec_output.argmax(dim=1)
        pred_token = out_vocab.itos[int(pred.item())]
        if pred_token == EOS:  # 当任一时间步搜索出EOS时，输出序列即完成
            break
        else:
            output_tokens.append(pred_token)
            dec_input = pred
    return output_tokens