Hfrxdjt

May I know how to correct the NameError: name 'xx' is not defined?

import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm, datasets
# import some data to play with
iris = datasets.load_iris()
X = iris.data[:,[2,3]]
y = iris.target

def plotSVC(title):
# create a mesh to plot in
 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 = (x_max / x_min)/100
 xx, yy = np.meshgrid(np.arange(x_min, x_max, h),
 np.arange(y_min, y_max, h))
 plt.subplot(1, 1, 1)
 Z = svc.predict(np.c_[xx.ravel(), yy.ravel()])
 Z = Z.reshape(xx.shape)

cs = [0.1, 1, 10, 100]
for c in cs:
 svc = svm.SVC(kernel='rbf', C=c).fit(X, y)
 plotSVC('C=' + str(c))

plt.contourf(xx, yy, Z, cmap=plt.cm.Paired, alpha=0.8)
plt.scatter(X[:, 0], X[:, 1], c=y, cmap=plt.cm.Paired)
plt.xlabel('petal length')
plt.ylabel('petal width')
plt.xlim(xx.min(), xx.max())
plt.show()

The error message is -

runfile('C:/Users/HSIPL/Desktop/Homework 5 6 Solution draft.py', wdir='C:/Users/HSIPL/Desktop')
C:/Users/HSIPL/Desktop/Homework 5 6 Solution draft.py:13: RuntimeWarning: divide by zero encountered in double_scalars
 h = (x_max / x_min)/100
C:UsersHSIPLAnaconda3libsite-packagesmatplotlibcbookdeprecation.py:107: MatplotlibDeprecationWarning: Adding an axes using the same arguments as a previous axes currently reuses the earlier instance. In a future version, a new instance will always be created and returned. Meanwhile, this warning can be suppressed, and the future behavior ensured, by passing a unique label to each axes instance.
 warnings.warn(message, mplDeprecation, stacklevel=1)
Traceback (most recent call last):

 File "<ipython-input-6-1b30b44bc6a6>", line 1, in <module>
 runfile('C:/Users/HSIPL/Desktop/Homework 5 6 Solution draft.py', wdir='C:/Users/HSIPL/Desktop')

 File "C:UsersHSIPLAnaconda3libsite-packagesspyder_kernelscustomizespydercustomize.py", line 668, in runfile
 execfile(filename, namespace)

 File "C:UsersHSIPLAnaconda3libsite-packagesspyder_kernelscustomizespydercustomize.py", line 108, in execfile
 exec(compile(f.read(), filename, 'exec'), namespace)

 File "C:/Users/HSIPL/Desktop/Homework 5 6 Solution draft.py", line 25, in <module>
 plt.contourf(xx, yy, Z, cmap=plt.cm.Paired, alpha=0.8)

NameError: name 'xx' is not defined

Why I get the new error for Z array -

import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm, datasets
# import some data to play with
iris = datasets.load_iris()
X = iris.data[:,[2,3]]
y = iris.target

def plotSVC(title):

 cs = [0.1, 1, 10, 100]
for c in cs:
 svc = svm.SVC(kernel='rbf', C=c).fit(X, y)
 plotSVC('C=' + str(c)) 
# create a mesh to plot in
 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 = (x_max / x_min)/100
 xx, yy = np.meshgrid(np.arange(x_min, x_max, h),
 np.arange(y_min, y_max, h))
 plt.subplot(1, 1, 1)
 Z = svc.predict(np.c_[xx.ravel(), yy.ravel()])
 Z = Z.reshape(xx.shape)

plt.contourf(xx, yy, Z, cmap=plt.cm.Paired, alpha=0.8)
plt.scatter(X[:, 0], X[:, 1], c=y, cmap=plt.cm.Paired)
plt.xlabel('petal length')
plt.ylabel('petal width')
plt.xlim(xx.min(), xx.max())
plt.show()

You did not define outside the plotSVC block.

One possible fix is to include

xx, yy = np.meshgrid(np.arange(x_min, x_max, h),
 np.arange(y_min, y_max, h))

before the

plt.contourf(xx, yy, Z, cmap=plt.cm.Paired, alpha=0.8)

line. Also, it seems to me that you might want to return something from the function definition, possibly $Z$. $Z$ is also not defined outside of function definition.

Make sure every variable is defined and visible (in the right scope) before we use it.