How to find minimum value from an array

Question

I'm new to python so the code may not be the best. I'm trying to find the minimum Total Cost (TotalC) and the corresponding m,k and xM values that go with this minimum cost. I'm not sure how to do this. I have tried using min(TotalC) however this gives an error within the loop or outside the loop only returns the value of TotalC and not the corresponding m, k, and xM values. Any help would be appreciated. This section is at the end of the code, I have included my entire code.

    import numpy as np
    import matplotlib.pyplot as plt
    
    
    def Load(x):
        Fpeak = (1000 + (9*(x**2) - (183*x))) *1000     #Fpeak in N
        td = (20 - ((0.12)*(x**2)) + (4.2*(x))) / 1000  #td in s
        
        return Fpeak, td
    
    #####################################################################################################
    ####################### Part 2 ########################
    
    def displacement(m,k,x,dt):           #Displacement function
    
        Fpeak, td = Load(x)               #Load Function from step 1
        
        w = np.sqrt(k/m)                  # Natural circular frequency
        T = 2 * np.pi /w                  #Natural period of blast (s)
        time = np.arange(0,2*T,0.001)     #Time array with range (0 - 2*T) with steps of 2*T/100
        
        
        zt = []                           #Create a lsit to store displacement values
        for t in time:
                if (t <= td):
                    zt.append((Fpeak/k) * (1 - np.cos(w*t)) + (Fpeak/(k*td)) * ((np.sin(w*t)/w) - t))
                else:
                    zt.append((Fpeak/(k*w*td)) * (np.sin(w*t) - np.sin(w*(t-td))) - ((Fpeak/k) * np.cos(w*t))) 
                    
        
        zmax=max(zt)            #Find the max displacement from the list of zt values
        return zmax             #Return max displacement
    
    k = 1E6
    m = 200
    dt = 0.0001
    x = 0
    
    
    z = displacement(m,k,x,dt)
    
    ###################################################################################
    ############### Part 3 #######################
    # k = 1E6 , m = 200kg , Deflection = 0.1m
    
    
    k_values = np.arange(1E6, 7E6, ((7E6-1E6)/10))   #List of k values between min and max (1E6 and 7E6).
    m_values = np.arange(200,1200,((1200-200)/10))   #List of m values between min and max 200kg and 1200kg
    
    xM = []
    
    for k in k_values: # values of k
        for m in m_values: # values of m within k for loop
        
    
            def bisector(m,k,dpoint,dt):  #dpoint = decimal point accuracy
                 xL = 0
                 xR = 10
                 xM = (xL + xR)/2
                 zmax = 99
    
                 while round(zmax, dpoint) !=0.1:
                     zmax = displacement(m,k,xM,dt)
                     if zmax > 0.1:
                         xL = xM
                         xM = (xL + xR)/2
                     else:
                         xR = xM
                         xM = (xL + xR)/2
                 return xM
    
            xM = bisector(m, k, 4, 0.001)
            print('xM value =',xM)
        
####################################################################################        
            def cost (m,k,xM):
            
                Ck = np.array(900 + 825*((k/1E6)**2) - (1725*(k/1E6)))
                Cm = np.array(10*m - 2000)
                Cx = np.array(2400*((xM**2)/4))
                TotalC = Ck + Cm + Cx
                print(TotalC)
                print(min(TotalC))
                return TotalC
        
            TotalC = cost(m, k, xM)
        
            print([xM, m, k, TotalC])

John Zwinck · Accepted Answer · 2021-12-23 12:11:21Z

1

You want this:

minIndex = TotalC.argmin()

Now you use that numeric index into all your arrays TotalC, Ck, Cm and Cx.

answered Dec 23, 2021 at 12:11

John Zwinck

252k44 gold badges346 silver badges459 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

KMR Over a year ago

Thanks that's what I was looking for, where exactly am I supposed to put this within my code?

Muneeb · Accepted Answer · 2021-12-23 12:10:05Z

0

find the index of the min value in total and the index should be same for corresponding arrays.

answered Dec 23, 2021 at 12:10

Muneeb

135 bronze badges

1 Comment

Community Over a year ago

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.

Collectives™ on Stack Overflow

How to find minimum value from an array

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related