i am trying to plot the probability of failure with respect to any other parameter buy some reason Ds gets to be NaN value. this is the Code:

clear all;
%mub=65;
sigb=4;
muk3=1.1;
sigk3=0.1;
mus=0.0032;
sigs=0.016;
mun=0.035;
sign=0.01;
mud=2;
sigd=0.1;
j=1
for mub=60:1:100
    [Ds] = Demandofscour(mub,sigb,muk3,sigk3,mus,sigs,mun,sign,mud,sigd);
    count=nnz(4-Ds(:)<0);
    total=size(Ds,2);
    mub1(j)=mub;
    p(j)=count/total;
    j=j+1;
end
plot(mub1,p)

'''

This is the Demandofscour file code:

'''

function [Ds] = Demandofscour(mub,sigb,muk3,sigk3,mus,sigs,mun,sign,mud,sigd)
Q=300;
k1=1;
k2=1;
k4=1;
g=9.81;
for i=1:700
b(i)=normrnd(mub,sigb);
k3(i)=unifrnd(muk3,sigk3);
s(i)=lognrnd(mus,sigs);
n(i)=lognrnd(mun,sign);
d(i)=normrnd(mud,sigd);
yo(i)=(Q.*n(i))./(b(i).*(s(i)^0.5))^(3/5);
v(i)=Q./(b(i).*yo(i));
f(i)=v(i)./(((g.*yo(i))^0.5));
Ds(i)=2*k1*k2.*k3(i)*k4.*((d(i)/yo(i))^0.65).*(f(i)^0.43);
end
end

'''

please if you guys know what to do help me.