How do I plot a function with input in y-axis and output in x-axis

Question

I am doing a nonlinear two-class classification and the data has three dimension x=data[:,0] y= data[:,1], z=data[:,2].

I want to draw a decision boundary on the xy plane and also the scattering data simultaneously, to see if it fit well to the data. The result function I got is a sinusoidal function with y being input and x being output like this:

x= 2.2*sin(0.44 - 0.69*y) - 0.61

I an new to python and have trouble plotting this. Now I have wrote something like this:

x,y,c = np.loadtxt('bricks.csv',delimiter=',', unpack=True)
plt.scatter(x,y,c=c) 
plt.show()



def decision_boundary(x_2):
    x_1= float(2.2)*np.sin(0.44 - 0.69*x_2) - 0.61
    return x_1

x2 = np.arange(-5.0, 5.0, 0.1)
plt.plot(decision_boundary(x2),x2)

,which give a wrong figure.Could someone help me out? Thanks!

Answer 1

Just swap the values you are passing to plot.

import matplotlib.pyplot as plt
def decision_boundary(x_2):
    x_1= float(2.2)*np.sin(0.44 - 0.69*x_2) - 0.61
    return x_1

x2 = np.arange(-5.0, 5.0, 0.1)
plt.plot(x2,decision_boundary(x2))
plt.show()