from d2l import torch as d2l
import torch
from torch import nn
import matplotlib as mpl
mpl.use('MacOSX')
# n_train = 50 # No. of training examples
n_train = 300 # No. of training examples
x_train, _ = torch.sort(d2l.rand(n_train) * 5) # Training inputs
def f(x):
return 2 * d2l.sin(x) + x**0.8
y_train = f(x_train) + d2l.normal(0.0, 0.5, (n_train,)) # Training outputs
x_test = d2l.arange(0, 5, 0.1) # Testing examples
y_truth = f(x_test) # Ground-truth outputs for the testing examples
n_test = len(x_test) # No. of testing examples
n_test
def plot_kernel_reg(y_hat):
d2l.plot(x_test, [y_truth, y_hat], 'x', 'y', legend=['Truth', 'Pred'],
xlim=[0, 5], ylim=[-1, 5])
d2l.plt.plot(x_train, y_train, 'o', alpha=0.5);
y_hat = torch.repeat_interleave(y_train.mean(), n_test)
plot_kernel_reg(y_hat)
from d2l import torch as d2l
import matplotlib.pyplot as plt
import torch
from torch import nn
#@tab mxnet, pytorch
T = 1000 # Generate a total of 1000 points
time = d2l.arange(1, T + 1, dtype=d2l.float32)
x = d2l.sin(0.01 * time) + d2l.normal(0, 0.2, (T, ))
d2l.plot(time, [x], 'time', 'x', xlim=[1, 1000], figsize=(6, 3))
plt.show()
#@tab mxnet, pytorch
tau = 4
features = d2l.zeros((T - tau, tau))
for i in range(tau):
features[:, i] = x[i:T - tau + i]
labels = d2l.reshape(x[tau:], (-1, 1))
batch_size, n_train = 16, 600
# Only the first `n_train` examples are used for training
train_iter = d2l.load_array((features[:n_train], labels[:n_train]),
batch_size,
is_train=True)
# Function for initializing the weights of the network
def init_weights(m):
if type(m) == nn.Linear:
nn.init.xavier_uniform_(m.weight)