import numpy as np
import matplotlib.pyplot as plt


def sigmoid(x,a,b):
# sigmoid function with parameters a = center; b = width
return 1/(1+np.exp(-(x-a)/b))

# testing changing sigmoid width (and slope at the same time) - parameter b
 x = np.linspace(0,10,256)
 y = sigmoid(x,5,1) # default
 ymax = sigmoid(x,5,1.75)
 ymin = sigmoid(x,5,0.25)
 # Create the plot
 plt.plot(x,y,lw=2,color='black')
 plt.plot(x,ymax,lw=2,color='green')
 plt.plot(x,ymin,lw=2,color='orange')

test=np.linspace(0,1,128)
plt.plot(y2*255,test,lw=2,color='yellow')