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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

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.