title: bool value of Tensor with more than one value is ambiguous Pytorch error
body: <p>I have a Neural network that i want to train but i keep getting an "bool value of Tensor with more than one value is ambiguous" Error. </p>
  
  <p>Here is my network:</p>
  
  <pre><code>from torch.autograd import Variable
  from torch.utils.data import Dataset, DataLoader
  import torch.nn as nn
  from torch.nn import functional as F
  from DataSetLoader import ReplaysDataSet
  
  
  class Model(nn.Module):
      def __init__(self):
          super(Model, self).__init__()
          self.l1 = torch.nn.Linear(12,24)
          self.l2 = torch.nn.Linear(24, 20)
          self.l3 = torch.nn.Linear(20, 16)
          self.l4 = torch.nn.Linear(16, 10)
          self.l5 = torch.nn.Linear(10, 6)
          self.l6 = torch.nn.Linear(6, 1)
  
      def forward(self, t):
          t = F.relu(self.l1(t))
          t = F.relu(self.l2(t))
          t = F.relu(self.l3(t))
          t = F.relu(self.l4(t))
          t = F.relu(self.l5(t))
          y_pred = F.relu(self.l6(t))
  
          return y_pred
      def get_num_correct(self,preds,labels):
          return preds.argmax(dim=1).eq(labels).sum()
  
  class Test():
      model = Model()
      optimiser = torch.optim.SGD(model.parameters(), lr=0.01)
  
      dataset = ReplaysDataSet()
      trainLoader = DataLoader(dataset=dataset, batch_size=250, shuffle=True)
      batch = next(iter(trainLoader))
      criterion = nn.MSELoss
      for epoch in range(10):
          totalLoss = 0
          totalCorrect = 0
          for batch in trainLoader:
  
              data, label = batch
              prediction = model(data)
              prediction = prediction.reshape(250)
              print(prediction)
              print(label)
              loss = criterion(prediction, label)
              optimiser.zero_grad()
  
              loss.backward()
              optimiser.step()
  
              totalLoss += loss.item()
              print(totalLoss)
              totalCorrect += model.get_num_correct(prediction, label)
              print(totalCorrect)
  </code></pre>
  
  <p>Here is my Data loader</p>
  
  <pre><code>import torch
  from torch.autograd import Variable
  from torch.utils.data import Dataset, DataLoader
  from torch.nn import functional as F
  
  class ReplaysDataSet(Dataset):
      def __init__(self):
          self.xy = np.genfromtxt("dataset.csv", delimiter=',', dtype=np.float32)
          self.length = len(self.xy)
          self.x_data = torch.from_numpy(self.xy[0:,1:])
          self.y_data = torch.from_numpy(self.xy[0:,0])
          self.length = len(self.xy)
      def __getitem__(self, index):
          return self.x_data[index], self.y_data[index]
      def __len__(self):
          return self.length
  </code></pre>
  
  <p>And here is some data from the csv im training on</p>
  
  <pre><code>1,303,497,784,748,743,169,462,479,785,310,26,701
  1,658,598,645,786,248,381,80,428,248,530,591,145
  0,38,490,796,637,130,380,226,359,720,392,464,497
  0,94,752,645,801,381,479,475,381,227,645,445,248
  0,59,806,254,521,91,538,212,645,609,227,545,531
  1,65,254,685,565,91,796,445,658,465,485,472,184
  1,385,248,211,612,82,38,485,652,212,373,563,26
  1,796,596,785,310,145,479,142,685,748,635,798,474
  1,380,658,485,645,36,598,806,428,786,798,645,113
  0,743,214,625,642,530,784,645,641,65,598,786,637
  </code></pre>
  
  <p>The error i get is </p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Users/tayya/PycharmProjects/untitled/NetworkFile.py", line 32, in &lt;module&gt;
      class Test():
    File "C:/Users/tayya/PycharmProjects/untitled/NetworkFile.py", line 50, in Test
      loss = criterion(prediction, label)
  File "C:\Users\tayya\PycharmProjects\untitled\venv\lib\site-packages\torch\nn\modules\loss.py", line 428, in __init__
  super(MSELoss, self).__init__(size_average, reduce, reduction)
    File "C:\Users\tayya\PycharmProjects\untitled\venv\lib\site-packages\torch\nn\modules\loss.py", line 12, in __init__
      self.reduction = _Reduction.legacy_get_string(size_average, reduce)
    File "C:\Users\tayya\PycharmProjects\untitled\venv\lib\site-packages\torch\nn\_reduction.py", line 36, in legacy_get_string
      if size_average and reduce:
  RuntimeError: bool value of Tensor with more than one value is ambiguous
  
  </code></pre>
  
  <p>Any help would be greatly appreciated. I'm new to NN's so if i made a glaring mistake, my apologies.</p>