To implement different membership functions used for fuzzification of inputs.

Membership_functions.py

# import package

import numpy as np
import matplotlib.pyplot as plt
import math

def trianguler_mf(x,a,b,c):
    if x<=a:
        return 0
    elif a <= x <= b:
        return (x-a)/(b-a)
    elif b <= x <= c:
        return (c-x)/(c-b)
    else:
        return 0

def triangular_main():
    x = list(range(0,100,1))
    y = []
    a = 20
    b = 60
    c = 80

    for i in range(0,100,1):
        y.append(trianguler_mf(i,a,b,c))

    display(x,y,'Trianguler MF')

def trapezoidal_mf(x,a,b,c,d):
    if x<=a:
        return 0
    elif a <= x <= b:
        return (x-a)/(b-a)
    elif b <= x <= c:
        return 1
    elif c<= x <= d:
        return (d-x)/(d-c)
    else:
        return 0

def trapezoidal_main():
    x = list(range(0,100,1))
    y = []
    a = 20
    b = 40
    c = 60
    d = 80
    for i in range(0,100,1):
        y.append(trapezoidal_mf(i,a,b,c,d))

    display(x,y,'Trapezoidal MF')

def gaussian_mf(x,c,sigma):
    m = -1/2 * ((x-c)**2) / (sigma)**2
    return math.exp(m)

def gaussian_main():
    x = list(range(0,100,1))
    y = []
    c = 50
    sigma = 20
    for i in range(0,100,1):
        y.append(gaussian_mf(i,c,sigma))

    display(x,y,'Gaussian MF')

def generalised_bell_mf(x,a,b,c):
    denominator = abs((x-c)/a)**(2*b)    
    return 1/ (1+denominator)

def generalised_bell_main():
    x = list(range(0,100,1))
    y = []
    a = 20
    b = 40
    c = 60 
    sigma = 20
    for i in range(0,100,1):
        y.append(generalised_bell_mf(i,a,b,c))

    display(x,y,'Generalised bell MF')

def sigmoid_mf(x,a,c):
    return (1 + math.exp(-a*(x-c)))**(-1)

def sigmoid_main():
    x = np.arange(0,10,0.1)
    y = []
    a = 2
    c = 4
    for i in x:
        y.append(sigmoid_mf(i,a,c))

    display(x,y,'Sigmoid MF')
    
def display(x,y,plot_name='Default'):
    '''
    Display : plot different graph
    '''
    plt.xlabel('X - Cordinates')
    plt.ylabel('Y - Cordinates')
    plt.plot(x,y,label=plot_name)
    plt.legend()
    plt.show()
    
if __name__=='__main__':
    triangular_main()
    trapezoidal_main()
    gaussian_main()
    generalised_bell_main()
    sigmoid_main()