import?matplotlib.pyplot?as?plt
import?numpy?as?np
import?sklearn
import?sklearn.datasets
import?sklearn.linear_model

def?plot_decision_boundary（model?X?y）:
????#?Set?min?and?max?values?and?give?it?some?padding
????x_min?x_max?=?X[0?:].min（）?-?1?X[0?:].max（）?+?1
????y_min?y_max?=?X[1?:].min（）?-?1?X[1?:].max（）?+?1
????h?=?0.01
????#?Generate?a?grid?of?points?with?distance?h?between?them
????xx?yy?=?np.meshgrid（np.arange（x_min?x_max?h）?np.arange（y_min?y_max?h））
????#?Predict?the?function?value?for?the?whole?grid
????Z?=?model（np.c_[xx.ravel（）?yy.ravel（）]）
????Z?=?Z.reshape（xx.shape）
????#?Plot?the?contour?and?training?examples
????plt.contourf（xx?yy?Z?cmap=plt.cm.Spectral）
????plt.ylabel（‘x2‘）
????plt.xlabel（‘x1‘）
????plt.scatter（X[0?:]?X[1?:]?c=y?cmap=plt.cm.Spectral）
????

def?sigmoid（x）:
????“““
????Compute?the?sigmoid?of?x

????Arguments:
????x?--?A?scalar?or?numpy?array?of?any?size.

????Return:
????s?--?sigmoid（x）
????“““
????s?=?1/（1+np.exp（-x））
????return?s

def?load_planar_dataset（）:
????np.random.seed（1）
????m?=?400?#?number?of?examples
????N?=?int（m/2）?#?number?of?points?per?class
????D?=?2?#?dimensionality
????X?=?np.zeros（（mD））?#?data?matrix?where?each?row?is?a?single?example
????Y?=?np.zeros（（m1）?dtype=‘uint8‘）?#?labels?vector?（0?for?red?1?for?blue）
????a?=?4?#?maximum?ray?of?the?flower

????for?j?in?range（2）:
????????ix?=?range（N*jN*（j+1））
????????t?=?np.linspace（j*3.12（j+1）*3.12N）?+?np.random.randn（N）*0.2?#?theta
????????r?=?a*np.sin（4*t）?+?np.random.randn（N）*0.2?#?radius
????????X[ix]?=?np.c_[r*np.sin（t）?r*np.cos（t）]
????????Y[ix]?=?j
????????
????X?=?X.T
????Y?=?Y.T

????return?X?Y

def?load_extra_datasets（）:??
????N?=?200
????noisy_circles?=?sklearn.datasets.make_circles（n_samples=N?factor=.5?noise=.3）
????noisy_moons?=?sklearn.datasets.make_moons（n_samples=N?noise=.2）
????blobs?=?sklearn.datasets.make_blobs（n_samples=N?random_state=5?n_features=2?centers=6）
????gaussian_quantiles?=?sklearn.datasets.make_gaussian_quantiles（mean=None?cov=0.5?n_samples=N?n_features=2?n_classes=2?shuffle=True?random_state=None）
????no_structure?=?np.random.rand（N?2）?np.random.rand（N?2）
????
????return?noisy_circles?noisy_moons?blobs?gaussian_quantiles?no_structure

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

????.......??????2253??2017-08-22?08:16??planar_utils.py

????.......?????????0??2017-08-22?08:16??readme.md

????.......??????3993??2017-08-22?08:16??testCases.py

????.......???1075865??2017-08-22?08:16??week3-Planar+data+classification+with+one+hidden+layer.ipynb

????.......????139115??2017-08-22?08:16??images\classification_kiank.png

????.......????681895??2017-08-22?08:16??images\grad_summary.png

????.......?????41671??2017-08-22?08:16??images\sgd.gif

????.......?????64014??2017-08-22?08:16??images\sgd_bad.gif

?????目錄??????????0??2017-08-22?08:16??images

-----------?---------??----------?-----??----

??????????????2008806????????????????????9