RuntimeError: Only last dimension is supported for softmax

[filipposkat]

Thank you for all your effort, OpenCL is really the only option for old AMD gpus. I have successfully managed to build your code on windows by following the instructions. There were some minor issues I would like to note in case you want to update README accordingly:

1. "-DCMAKE_INCLUDE_PATH=c:\deps\include\include" should be "-DCMAKE_INCLUDE_PATH=c:\deps\include"
2. Adding sqlit3.dll to path did not work for me (file not found error), probably due to this. I had to add this piece of code to my script: os.add_dll_directory("C:\deps\lib")

This was a sidenote, the real issue I have is that I get an error when trying to train a simple UNET using CrossEntropyLoss:

  File "G:\filip\Documents\Data Science Projects\Thesis\apnea-ppg\trainer.py", line 149, in train_loop
    loss = criterion(outputs, labels.long())
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\modules\module.py", line 1190, in _call_impl
    return forward_call(*input, **kwargs)
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\modules\loss.py", line 1174, in forward
    return F.cross_entropy(input, target, weight=self.weight,
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\functional.py", line 3026, in cross_entropy
    return torch._C._nn.cross_entropy_loss(input, target, weight, _Reduction.get_enum(reduction), ignore_index, label_smoothing)
RuntimeError: Only last dimension is supported for softmax

where criterion is: nn.CrossEntropyLoss() Is this normal?

Details: Number of classes: 5 My batches have this shape: (256, 1, 512) Output has shape: (256, 5, 512) Labels have shape: (256, 512)

Specs: OS: Windows 10 PyTorch version: 1.13 Python version: 3.10 GPU: RX 590

[artyom-beilis]

Can you use nll_loss - I implemeted full cross range for log loss but not for direct softmax (since it is rarely used as is)

[filipposkat]

Changed to:

m = nn.LogSoftmax(dim=1)
criterion = nn.NLLLoss()
loss = criterion(m(outputs), labels.long())

and I get:

  File "G:\filip\Documents\Data Science Projects\Thesis\apnea-ppg\trainer.py", line 155, in train_loop
    loss = criterion(m(outputs), labels.long())
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\modules\module.py", line 1190, in _call_impl
    return forward_call(*input, **kwargs)
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\modules\activation.py", line 1461, in forward
    return F.log_softmax(input, self.dim, _stacklevel=5)
  File "C:\Users\filip\anaconda3\envs\torch_113\lib\site-packages\torch\nn\functional.py", line 1930, in log_softmax
    ret = input.log_softmax(dim)
RuntimeError: Only last dimension is supported for softmax

[artyom-beilis]

Do you have latest version?

[artyom-beilis]

I added it around Nov 26.

[filipposkat]

Yes, cloned yesterday

[artyom-beilis]

Ok let me see what I can do.

Can you give me full example of your loss function?

[filipposkat]

Code for training one epoch:

    import torch
    import torch.nn as nn
    import torch.optim as optim
    from torch.utils.data import DataLoader

    device = "privateuseone:0"

    # Create Network:
    net = UNet(nclass=5, in_chans=1, max_channels=512, depth=5, layers=2, kernel_size=5, sampling_method="conv_stride")
    net = net.to(device)

    criterion = nn.CrossEntropyLoss()

    optim_kwargs = {"lr": 0.001, "momentum": 0.7}
    optimizer = optim.SGD(net.parameters(), **optim_kwargs)

    for (i, data) in enumerate(train_dataloader):
        inputs, labels = data

        inputs = inputs.to(device)
        labels = labels.to(device)

        optimizer.zero_grad()

        outputs = net(inputs)

        loss = criterion(outputs, labels.long())

        loss.backward()
        optimizer.step()

Code of UNet class:

class EncoderBlock(nn.Module):
    # Consists of Conv -> LeakyReLU(0.2) -> MaxPool
    def __init__(self, in_chans, out_chans, layers=2, kernel_size=3, sampling_factor=2, sampling_method="pooling"):
        super().__init__()
        self.in_chans = in_chans
        self.out_chans = out_chans
        self.layers = layers
        self.kernel_size = kernel_size
        self.sampling_factor = sampling_factor
        self.sampling_method = sampling_method

        self.encoder = nn.ModuleList()

        for _ in range(layers):
            self.encoder.append(nn.Conv1d(in_chans, out_chans, kernel_size=kernel_size, stride=1, padding="same"))
            self.encoder.append(nn.BatchNorm1d(out_chans))
            self.encoder.append(nn.LeakyReLU(0.2))
            in_chans = out_chans

        if sampling_method == "conv_stride" and sampling_factor > 1:
            diff = (kernel_size - sampling_factor)
            if diff % 2 == 0:
                ks = kernel_size
                pad = diff // 2
            else:
                ks = kernel_size + 1
                pad = (ks - sampling_factor) // 2

            self.encoder.append(nn.Sequential(
                nn.Conv1d(out_chans, out_chans, kernel_size=ks,
                          stride=sampling_factor, padding=pad),
                nn.BatchNorm1d(out_chans),
                nn.LeakyReLU(0.2)))
        elif sampling_method == "pooling" and sampling_factor > 1:
            self.encoder.append(nn.MaxPool1d(sampling_factor))

    def forward(self, x):
        for enc in self.encoder:
            x = enc(x)
        return x

class DecoderBlock(nn.Module):
    # Consists of 2x2 transposed convolution -> Conv -> LeakyReLU(0.2)
    def __init__(self, in_chans, out_chans, layers=2, kernel_size=3, skip_connection=True, sampling_factor=2,
                 dropout=0.0):
        super().__init__()
        self.skip_connection = skip_connection
        self.layers = layers
        self.kernel_size = kernel_size
        self.padding = "same"
        self.dropout = dropout

        skip_factor = 1 if skip_connection else 2
        self.decoder = nn.ModuleList()

        if kernel_size == sampling_factor:
            pad = 0
            out_pad = 0
        elif (kernel_size - sampling_factor) % 2 == 0:
            pad = (kernel_size - sampling_factor) // 2
            out_pad = 0
        else:
            out_pad = 1
            pad = (kernel_size - sampling_factor + out_pad) // 2

        assert (kernel_size - sampling_factor - 2 * pad + out_pad) == 0
        self.tconv = nn.ConvTranspose1d(in_chans, in_chans // 2, stride=sampling_factor, kernel_size=kernel_size,
                                        padding=pad, output_padding=out_pad)

        self.decoder.append(nn.Conv1d(in_chans // skip_factor, out_chans, kernel_size, 1, padding="same"))
        self.decoder.append(nn.BatchNorm1d(out_chans))
        self.decoder.append(nn.LeakyReLU(0.2))
        for _ in range(layers - 1):
            self.decoder.append(nn.Conv1d(out_chans, out_chans, kernel_size, 1, padding="same"))
            self.decoder.append(nn.BatchNorm1d(out_chans))
            self.decoder.append(nn.LeakyReLU(0.2))

        if dropout > 0.0:
            self.decoder.append(nn.Dropout(p=dropout))

    def forward(self, x, enc_features=None):
        x = self.tconv(x)
        if self.skip_connection:
            x = torch.cat((enc_features, x), dim=1)
        for dec in self.decoder:
            x = dec(x)
        return x

class UNet(nn.Module):
    def __init__(self, nclass=1, in_chans=1, max_channels=512, depth=5, layers=2, kernel_size=3, sampling_factor=2,
                 sampling_method="pooling", skip_connection=True):
        """
        :param nclass:
        :param in_chans:
        :param max_channels:
        :param depth:
        :param layers:
        :param kernel_size:
        :param sampling_factor:
        :param sampling_method: either "pooling" or "conv_stride"
        :param skip_connection:
        """
        super().__init__()
        self.nclass = nclass
        self.in_chans = in_chans
        self.max_channels = max_channels
        self.depth = depth
        self.layers = layers
        self.kernel_size = kernel_size
        self.sampling_factor = sampling_factor
        self.sampling_method = sampling_method
        self.skip_connection = skip_connection

        self.encoder = nn.ModuleList()
        self.decoder = nn.ModuleList()

        first_out_chans = max_channels // (2 ** (depth - 1))
        if first_out_chans % 4 == 0:
            out_chans = first_out_chans
        else:
            out_chans = 4

        # The first block should not do any down-sampling (stride = 1 and no pooling):
        self.encoder.append(EncoderBlock(in_chans, out_chans, layers, kernel_size=kernel_size,
                                         sampling_factor=1, sampling_method="no sampling"))

        for _ in range(depth - 1):
            if out_chans * 2 <= max_channels:
                in_chans, out_chans = out_chans, out_chans * 2
            else:
                in_chans, out_chans = out_chans, out_chans
            self.encoder.append(EncoderBlock(in_chans, out_chans, layers=layers, kernel_size=kernel_size,
                                             sampling_factor=sampling_factor, sampling_method=sampling_method))

        for _ in range(depth - 1):
            if out_chans // 2 >= 4:
                in_chans, out_chans = out_chans, out_chans // 2
            else:
                in_chans, out_chans = out_chans, out_chans
            self.decoder.append(DecoderBlock(in_chans, out_chans, layers=layers, kernel_size=kernel_size,
                                             sampling_factor=sampling_factor))

        # Add a 1x1 convolution to produce final classes
        self.logits = nn.Conv1d(out_chans, nclass, 1, 1)

    def forward(self, x):
        encoded = []
        for enc in self.encoder:
            x = enc(x)
            encoded.append(x)

        # Last encoder output is not used in any skip_connection:
        _ = encoded.pop()

        for dec in self.decoder:
            enc_output = encoded.pop()
            x = dec(x, enc_output)

        # Return the logits
        return self.logits(x)

train_loader yields two tensors (X, y) where

• X has shape: (256, 1, 512) and contains float32 numbers
• y has shape: (256, 512) and contains uint8 integers ranging from 0 to 4 (5 classes)

[artyom-beilis]

Got it.