Plotting reliability model code

Following is my code for degradation reliability. I just cannot figure out why it would not plot the graph. All I get is a straight line. Could anyone help me out? I need x axis to be time and y axis to be 0 to 1. Graph should look like decreasing from 1 to 0 over time.

function [j] = Reliability(N,i1,sigma1,bb,B1,T,k)

% i1 is initial value % sigma1 is sigma value % bb is mu value % B1 is Threshold value % T is Time % k is constant value which is 1

clf; % clear the entire figure

tt = (0:1:T)/N; % t is the column vector [0 1/N 2/N ... 1] tt = tt*T;

% Calculation for first phi, simplified to tenth p= (B1-i1-(bb*tt))/(sigma1*sqrt(tt)); p= roundn(p,-1); %round up to tenth

if p==0.0 % finding phi value l=.5*k; elseif p==0.1 l=.5478*k; elseif p==0.2 l=.5793*k; elseif p==0.3 l=.6255*k; elseif p==0.4 l=.6554*k; elseif p==0.5 l=.6985*k; elseif p==0.6 l=.7257*k; elseif p==0.7 l=.7642*k; elseif p==0.8 l=.7881*k; elseif p==0.9 l=.8212*k; elseif p==1.0 l=.8413*k; elseif p==1.1 l=.8686*k; elseif p==1.2 l=.8849*k; elseif p==1.3 l=.9066*k; elseif p==1.4 l=.9192*k; elseif p==1.5 l=.9357*k; elseif p==1.6 l=.9452*k; elseif p==1.7 l=.9573*k; elseif p==1.8 l=.9641*k; elseif p==1.9 l=.9726*k; elseif p==2.0 l=.9772*k; elseif p==2.1 l=.9830*k; elseif p==2.2 l=.9861*k; elseif p==2.3 l=.9898*k; elseif p==2.4 l=.9918*k; elseif p==2.5 l=.9941*k; elseif p==2.6 l=.9953*k; elseif p==2.7 l=.9967*k; elseif p==2.8 l=.9974*k; elseif p==2.9 l=.9982*k; elseif p==3.0 l=.9987*k; elseif p>3.0 l=1*k; elseif p==-0.1 l=.4522*k; elseif p==-0.2 l=.4207*k; elseif p==-0.3 l=.3745*k; elseif p==-0.4 l=.3446*k; elseif p==-0.5 l=.3015*k; elseif p==-0.6 l=.2743*k; elseif p==-0.7 l=.2358*k; elseif p==-0.8 l=.2119*k; elseif p==-0.9 l=.1788*k; elseif p==-1.0 l=.1587*k; elseif p==-1.1 l=.1314*k; elseif p==-1.2 l=.1151*k; elseif p==-1.3 l=.0934*k; elseif p==-1.4 l=.0808*k; elseif p==-1.5 l=.0643*k; elseif p==-1.6 l=.0548*k; elseif p==-1.7 l=.0427*k; elseif p==-1.8 l=.0359*k; elseif p==-1.9 l=.0274*k; elseif p==-2.0 l=.0228*k; elseif p==-2.1 l=.0170*k; elseif p==-2.2 l=.0139*k; elseif p==-2.3 l=.0102*k; elseif p==-2.4 l=.0082*k; elseif p==-2.5 l=.0059*k; elseif p==-2.6 l=.0047*k; elseif p==-2.7 l=.0033*k; elseif p==-2.8 l=.0026*k; elseif p==-2.9 l=.0018*k; elseif p==-3.0 l=.0013*k;

else l=0*k; end

% Calculation for first phi, simplified to tenth p1=-1*((B1-i1+bb*tt)/(sigma1*sqrt(tt))); p1= roundn(p1,-1); %round up to tenth

if p1==0.0 % finding phi value l1=.5; elseif p1==0.1 l1=.5478*k; elseif p1==0.2 l1=.5793*k; elseif p1==0.3 l1=.6255*k; elseif p1==0.4 l1=.6554*k; elseif p1==0.5 l1=.6985*k; elseif p1==0.6 l1=.7257*k; elseif p1==0.7 l1=.7642*k; elseif p1==0.8 l1=.7881*k; elseif p1==0.9 l1=.8212*k; elseif p1==1.0 l1=.8413*k; elseif p1==1.1 l1=.8686*k; elseif p1==1.2 l1=.8849*k; elseif p1==1.3 l1=.9066*k; elseif p1==1.4 l1=.9192*k; elseif p1==1.5 l1=.9357*k; elseif p1==1.6 l1=.9452*k; elseif p1==1.7 l1=.9573*k; elseif p1==1.8 l1=.9641*k; elseif p1==1.9 l1=.9726*k; elseif p1==2.0 l1=.9772*k; elseif p1==2.1 l1=.9830*k; elseif p1==2.2 l1=.9861*k; elseif p1==2.3 l1=.9898*k; elseif p1==2.4 l1=.9918*k; elseif p1==2.5 l1=.9941*k; elseif p1==2.6 l1=.9953*k; elseif p1==2.7 l1=.9967*k; elseif p1==2.8 l1=.9974*k; elseif p1==2.9 l1=.9982*k; elseif p1==3.0 l1=.9987*k; elseif p1>3.0 l1=1*k; elseif p1==-0.1 l1=.4522*k; elseif p1==-0.2 l1=.4207*k; elseif p1==-0.3 l1=.3745*k; elseif p1==-0.4 l1=.3446*k; elseif p1==-0.5 l1=.3015*k; elseif p1==-0.6 l1=.2743*k; elseif p1==-0.7 l1=.2358*k; elseif p1==-0.8 l1=.2119*k; elseif p1==-0.9 l1=.1788*k; elseif p1==-1.0 l1=.1587*k; elseif p1==-1.1 l1=.1314*k; elseif p1==-1.2 l1=1.1151*k; elseif p1==-1.3 l1=.0934*k; elseif p1==-1.4 l1=.0808*k; elseif p1==-1.5 l1=.0643*k; elseif p1==-1.6 l1=.0548*k; elseif p1==-1.7 l1=.0427*k; elseif p1==-1.8 l1=.0359*k; elseif p1==-1.9 l1=.0274*k; elseif p1==-2.0 l1=.0228*k; elseif p1==-2.1 l1=.0170*k; elseif p1==-2.2 l1=.0139*k; elseif p1==-2.3 l1=.0102*k; elseif p1==-2.4 l1=.0082*k; elseif p1==-2.5 l1=.0059*k; elseif p1==-2.6 l1=.0047*k; elseif p1==-2.7 l1=.0033*k; elseif p1==-2.8 l1=.0026*k; elseif p1==-2.9 l1=.0018*k; elseif p1==-3.0 l1=.0013*k;

else l1=0*k; end

%reliability equation %l and l1 has been already calculated j=(l*tt-(exp((2*bb*(B1-i1))/sigma1^2)*(l1*tt))); plot(tt,j);

Thanks in advance.