Appendix A.4

[Oderlesspanic]

I get an error returned for this and i have no idea how to fix it

I write in Spyder 5.4.3 with Python 3.11

codeline:

`import torch
import torchvision as TV
import numpy as np
from matplotlib import pyplot as plt

def nn(x,w1,w2):
l1 = x @ w1
l1 = torch.relu(l1)
l2 = l1 @ w2
return l2

w1 = torch.randn(784,200,requires_grad=True)
w2 = torch.randn(200,10,requires_grad=True)

mnist_data = TV.datasets.MNIST("MNIST", train=True, download=False)

plt.figure(figsize=(10,7))
plt.imshow(mnist_data.train_data[0])
plt.axis('off')

lr = 0.0001
epochs = 2500
batch_size = 1000
losses = []
lossfn = torch.nn.CrossEntropyLoss()
for i in range(epochs):
rid = np.random.randint(0,mnist_data.train_data.shape[0],size=batch_size)
x = mnist_data.train_data[rid].float().flatten(start_dim=1)
x /= x.max()
pred = nn(x,w1,w2)
target = mnist_data.train_labels[rid]
loss = lossfn(pred,target)
losses.append(loss)
loss.backward()
with torch.no_grad():
w1 -= lr * w1.grad
w2 -= lr * w2.grad

plt.figure(figsize=(10,7))
plt.xlabel("Training Time", fontsize=22)
plt.ylabel("Loss", fontsize=22)
plt.plot(losses)`

console return:

File ~/anaconda3/lib/python3.11/site-packages/spyder_kernels/py3compat.py:356 in compat_exec
exec(code, globals, locals)

File ~/.spyder-py3/temp.py:49
plt.plot(losses)

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/pyplot.py:2812 in plot
return gca().plot(

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/axes/_axes.py:1688 in plot
lines = [*self._get_lines(*args, data=data, **kwargs)]

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/axes/_base.py:311 in call
yield from self._plot_args(

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/axes/_base.py:496 in _plot_args
x, y = index_of(xy[-1])

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/cbook/init.py:1661 in index_of
y = _check_1d(y)

File ~/anaconda3/lib/python3.11/site-packages/matplotlib/cbook/init.py:1353 in _check_1d
return np.atleast_1d(x)

File <array_function internals>:200 in atleast_1d

File ~/anaconda3/lib/python3.11/site-packages/numpy/core/shape_base.py:65 in atleast_1d
ary = asanyarray(ary)

File ~/anaconda3/lib/python3.11/site-packages/torch/_tensor.py:956 in array
return self.numpy()

RuntimeError: Can't call numpy() on Tensor that requires grad. Use tensor.detach().numpy() instead.

[Oderlesspanic]

i solve it, use this

plt.plot([loss.item() for loss in losses])

instead of this

plt.plot(losses)