SSTF.py

def SSTF(sequence,start):
    temp = sequence.copy()
    def next_in_sequence(seq,val):
        diff = 0
        mindiff = math.inf
        nextval = 0
        #print(seq)
        for i in range(0,len(seq)):
            if(seq[i]!=val):
                diff = abs(seq[i]-val)
                if(diff<mindiff):
                    mindiff=diff
                    nextval = seq[i]
        return nextval
    
    temp.insert(0,start)
    val = start
    x = []
    y = []
    size = 0
    x.append(start)
    headmovement = 0
    while(len(temp)):
        val = next_in_sequence(temp,val)
        #print(val)
        x.append(val)
        temp.remove(val)
    size = len(x)
    for i in range(0,size):
        y.append(-i)
        if i!=(size-1):
            headmovement = headmovement + abs(x[i]-x[i+1])
    string = 'Headmovement = ' + str(headmovement) + ' cylinders'
    string2 = str(x)
    
    plt.plot(x,y, color="green", markerfacecolor = 'blue', marker='o', markersize = 5, linewidth = 2, label="SSTF")
    plt.ylim = (0,size)
    plt.xlim = (0,CYLINDER_MAX)
    plt.yticks([])
    plt.title("Shortest Seek Time First Scheduling Algorithm")
    plt.text(182.5, -10.85, string, horizontalalignment='center',verticalalignment='center',fontsize=12)
    plt.text(182.5, -11.5, string2, horizontalalignment='center',verticalalignment='center',fontsize=12)
    plt.show()