# Credit: https://github.com/karpathy/micrograd/blob/master/demo.ipynb # cell import datetime import random import matplotlib.pyplot as plt import numpy as np # cell from micrograd.engine import Value from micrograd.nn import MLP, Layer, Neuron print_statements = [] def run_all_micrograd_demo(*args, **kwargs): result = micrograd_demo() pyscript.write("micrograd-run-all-fig2-div", result) def print_div(o): o = str(o) print_statements.append(o + " \n
") pyscript.write("micrograd-run-all-print-div", "".join(print_statements)) # All code is wrapped in this run_all function so it optionally executed (called) # from pyscript when a button is pressed. def micrograd_demo(*args, **kwargs): """ Runs the micrograd demo. *args and **kwargs do nothing and are only there to capture any parameters passed from pyscript when this function is called when a button is clicked. """ # cell start = datetime.datetime.now() print_div("Starting...") # cell np.random.seed(1337) random.seed(1337) # cell # An adaptation of sklearn's make_moons function https://scikit-learn.org/stable/modules/generated/sklearn.datasets.make_moons.html def make_moons(n_samples=100, noise=None): n_samples_out, n_samples_in = n_samples, n_samples outer_circ_x = np.cos(np.linspace(0, np.pi, n_samples_out)) outer_circ_y = np.sin(np.linspace(0, np.pi, n_samples_out)) inner_circ_x = 1 - np.cos(np.linspace(0, np.pi, n_samples_in)) inner_circ_y = 1 - np.sin(np.linspace(0, np.pi, n_samples_in)) - 0.5 X = np.vstack( [ np.append(outer_circ_x, inner_circ_x), np.append(outer_circ_y, inner_circ_y), ] ).T y = np.hstack( [ np.zeros(n_samples_out, dtype=np.intp), np.ones(n_samples_in, dtype=np.intp), ] ) if noise is not None: X += np.random.normal(loc=0.0, scale=noise, size=X.shape) return X, y X, y = make_moons(n_samples=100, noise=0.1) # cell y = y * 2 - 1 # make y be -1 or 1 # visualize in 2D plt.figure(figsize=(5, 5)) plt.scatter(X[:, 0], X[:, 1], c=y, s=20, cmap="jet") plt pyscript.write("micrograd-run-all-fig1-div", plt) # cell model = MLP(2, [16, 16, 1]) # 2-layer neural network print_div(model) print_div(("number of parameters", len(model.parameters()))) # cell # loss function def loss(batch_size=None): # inline DataLoader :) if batch_size is None: Xb, yb = X, y else: ri = np.random.permutation(X.shape[0])[:batch_size] Xb, yb = X[ri], y[ri] inputs = [list(map(Value, xrow)) for xrow in Xb] # forward the model to get scores scores = list(map(model, inputs)) # svm "max-margin" loss losses = [(1 + -yi * scorei).relu() for yi, scorei in zip(yb, scores)] data_loss = sum(losses) * (1.0 / len(losses)) # L2 regularization alpha = 1e-4 reg_loss = alpha * sum((p * p for p in model.parameters())) total_loss = data_loss + reg_loss # also get accuracy accuracy = [ ((yi).__gt__(0)) == ((scorei.data).__gt__(0)) for yi, scorei in zip(yb, scores) ] return total_loss, sum(accuracy) / len(accuracy) total_loss, acc = loss() print((total_loss, acc)) # cell # optimization for k in range(20): # was 100 # forward total_loss, acc = loss() # backward model.zero_grad() total_loss.backward() # update (sgd) learning_rate = 1.0 - 0.9 * k / 100 for p in model.parameters(): p.data -= learning_rate * p.grad if k % 1 == 0: # print(f"step {k} loss {total_loss.data}, accuracy {acc*100}%") print_div(f"step {k} loss {total_loss.data}, accuracy {acc*100}%") # cell h = 0.25 x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1 y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1 xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h)) Xmesh = np.c_[xx.ravel(), yy.ravel()] inputs = [list(map(Value, xrow)) for xrow in Xmesh] scores = list(map(model, inputs)) Z = np.array([(s.data).__gt__(0) for s in scores]) Z = Z.reshape(xx.shape) fig = plt.figure() plt.contourf(xx, yy, Z, cmap=plt.cm.Spectral, alpha=0.8) plt.scatter(X[:, 0], X[:, 1], c=y, s=40, cmap=plt.cm.Spectral) plt.xlim(xx.min(), xx.max()) plt.ylim(yy.min(), yy.max()) finish = datetime.datetime.now() print_div(f"It took {(finish-start).seconds} seconds to run this code.") plt return plt