回答編集履歴
5
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answer
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@@ -7,6 +7,6 @@
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書籍のコードは GitHub に上がっているようなので、動かない場合はこちらのものと比較すると思います。
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書籍のコードは GitHub に上がっているようなので、動かない場合はこちらのものと比較するとよいかと思います。
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[python-machine-learning-book-2nd-edition/ch03.ipynb at master · rasbt/python-machine-learning-book-2nd-edition](https://github.com/rasbt/python-machine-learning-book-2nd-edition/blob/master/code/ch03/ch03.ipynb)
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4
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answer
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@@ -1,89 +1,12 @@
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1
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コピペミスだと思いますが、シグモイド関数の分母の指数が e^{-x} でなく、e^x になっていて、間違っています。
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2
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```diff
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- 1.0 / (1.0 + np.exp(np.clip(z, -250, 250)))
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+ 1.0 / (1.0 + np.exp(-np.clip(z, -250, 250)))
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```
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```python
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import matplotlib.pyplot as plt
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import numpy as np
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from sklearn.datasets import make_blobs
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from sklearn.linear_model import LogisticRegression
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10
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書籍のコードは GitHub に上がっているようなので、動かない場合はこちらのものと比較すると思います。
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def __init__(self, eta=0.05, n_iter=100, random_state=1):
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self.eta = eta
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self.n_iter = n_iter
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self.random_state = random_state
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def fit(self, X, y):
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rgen = np.random.RandomState(self.random_state)
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self.w_ = rgen.normal(loc=0.0, scale=0.01, size=1 + X.shape[1])
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self.cost_ = []
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for i in range(self.n_iter):
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net_input = self.net_input(X)
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output = self.activation(net_input)
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errors = y - output
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self.w_[1:] += self.eta * X.T.dot(errors)
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self.w_[0] += self.eta * errors.sum()
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cost = -y.dot(np.log(output)) - ((1 - y).dot(np.log(1 - output)))
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self.cost_.append(cost)
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return self
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def net_input(self, X):
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return np.dot(X, self.w_[1:]) + self.w_[0]
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def activation(self, z):
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return 1.0 / (1.0 + np.exp(-np.clip(z, -250, 250)))
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def predict(self, X):
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return np.where(self.net_input(X) >= 0.0, 1, 0)
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def plot_decision_regions(x, y, classifier, test_idx=None, resolution=0.02):
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markers = ("s", "x", "o", "^", "v")
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colors = ("blue", "red", "lightgreen", "gray", "cyan")
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cmap = ListedColormap(colors[: len(np.unique(y))])
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x1_min, x1_max = x[:, 0].min() - 1, x[:, 0].max() + 1
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x2_min, x2_max = x[:, 1].min() - 1, x[:, 1].max() + 1
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xx1, xx2 = np.meshgrid(
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np.arange(x1_min, x1_max, resolution), np.arange(x2_min, x2_max, resolution)
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)
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z = classifier.predict(np.array([xx1.ravel(), xx2.ravel()]).T)
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z = z.reshape(xx1.shape)
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plt.contourf(xx1, xx2, z, alpha=0.8, cmap=cmap)
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plt.xlim(xx1.min(), xx1.max())
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plt.ylim(xx2.min(), xx2.max())
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for idx, c1 in enumerate(np.unique(y)):
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plt.scatter(
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x=x[y == c1, 0],
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y=x[y == c1, 1],
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alpha=0.8,
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c=colors[idx],
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marker=markers[idx],
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label=c1,
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edgecolor="black",
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)
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# データを作成する。
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X, y = make_blobs(
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random_state=0, n_samples=200, n_features=2, cluster_std=0.8, centers=2
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)
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# ロジスティック回帰モデルで学習する。
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model = LogisticRegressionGD(eta=0.05, n_iter=1000, random_state=1).fit(X, y)
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plot_decision_regions(X, y, model)
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```
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もし、上記のようにならない場合は、現状の図を質問欄に貼ってください
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12
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+
[python-machine-learning-book-2nd-edition/ch03.ipynb at master · rasbt/python-machine-learning-book-2nd-edition](https://github.com/rasbt/python-machine-learning-book-2nd-edition/blob/master/code/ch03/ch03.ipynb)
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3
d
answer
CHANGED
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@@ -6,15 +6,42 @@
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6
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```python
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import matplotlib.pyplot as plt
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import numpy as np
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from matplotlib.colors import ListedColormap
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from sklearn.datasets import make_blobs
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from sklearn.linear_model import LogisticRegression
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# データを作成する。
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X, y = make_blobs(
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random_state=0, n_samples=200, n_features=2, cluster_std=0.8, centers=2
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)
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class LogisticRegressionGD(object):
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def __init__(self, eta=0.05, n_iter=100, random_state=1):
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self.eta = eta
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self.n_iter = n_iter
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self.random_state = random_state
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def fit(self, X, y):
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rgen = np.random.RandomState(self.random_state)
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self.w_ = rgen.normal(loc=0.0, scale=0.01, size=1 + X.shape[1])
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self.cost_ = []
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for i in range(self.n_iter):
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net_input = self.net_input(X)
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output = self.activation(net_input)
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errors = y - output
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self.w_[1:] += self.eta * X.T.dot(errors)
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self.w_[0] += self.eta * errors.sum()
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cost = -y.dot(np.log(output)) - ((1 - y).dot(np.log(1 - output)))
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self.cost_.append(cost)
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return self
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def net_input(self, X):
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return np.dot(X, self.w_[1:]) + self.w_[0]
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def activation(self, z):
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return 1.0 / (1.0 + np.exp(-np.clip(z, -250, 250)))
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def predict(self, X):
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return np.where(self.net_input(X) >= 0.0, 1, 0)
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def plot_decision_regions(x, y, classifier, test_idx=None, resolution=0.02):
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markers = ("s", "x", "o", "^", "v")
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colors = ("blue", "red", "lightgreen", "gray", "cyan")
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@@ -46,8 +73,14 @@
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)
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# データを作成する。
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X, y = make_blobs(
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random_state=0, n_samples=200, n_features=2, cluster_std=0.8, centers=2
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)
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# ロジスティック回帰モデルで学習する。
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model =
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model = LogisticRegressionGD(eta=0.05, n_iter=1000, random_state=1).fit(X, y)
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plot_decision_regions(X, y, model)
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```
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2
d
answer
CHANGED
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@@ -6,8 +6,6 @@
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6
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```python
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import matplotlib.pyplot as plt
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import numpy as np
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from matplotlib.colors import ListedColormap
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from sklearn import datasets
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from sklearn.datasets import make_blobs
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from sklearn.linear_model import LogisticRegression
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1
d
answer
CHANGED
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@@ -53,4 +53,6 @@
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plot_decision_regions(X, y, model)
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```
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もし、上記のようにならない場合は、現状の図を質問欄に貼ってください
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