1 files changed, 47 insertions, 0 deletions
diff --git a/learn_torch/basics/nn_demo.py b/learn_torch/basics/nn_demo.py
new file mode 100644
index 0000000..2e0bb98
--- /dev/null
+++ b/learn_torch/basics/nn_demo.py
@@ -0,0 +1,47 @@
+
+import torch
+import math
+
+
+device = 'cuda:0' if torch.cuda.is_available() else 'cpu'
+dtype = torch.float
+lr = 1e-6
+
+
+def train(X, y):
+    for i in range(2000):
+        y_pred = model(X)
+        loss = loss_fn(y_pred, y)
+
+        if i % 100 == 0:
+            print('{}/{}: {}'.format(i, 2000, loss.item()))
+
+        model.zero_grad()
+        loss.backward()
+
+        with torch.no_grad():
+            for param in model.parameters():
+                param -= lr * param.grad
+
+if __name__ == '__main__':
+
+    X = torch.linspace(-math.pi, math.pi, 2000, device=device, dtype=dtype)
+    y = torch.sin(X)
+
+    p = torch.Tensor([1, 2, 3])
+    X = X.unsqueeze(-1).pow(p)
+
+    model = torch.nn.Sequential(
+        torch.nn.Linear(3, 1),
+        torch.nn.Flatten(0, 1)
+    )
+
+    loss_fn = torch.nn.MSELoss()
+
+    train(X, y)
+    weight_layer = model[0]
+
+    print('y = {} + {}x + {}x^2 + {}x^3'.format(weight_layer.bias.item(),
+                                                weight_layer.weight[0, 0].item(),
+                                                weight_layer.weight[0, 1].item(),
+                                                weight_layer.weight[0, 2].item()))