Need help to put condition in my optimization function

Here is my code:

function T0=tw0Solve(t1,s1,s2,rho,P)
    T0= fsolve(@(tw0) (exp(-s2.^2./2).*exp(tw0.*s2).*(1-qfunc((t1-s1-rho.*tw0+rho.*s2)./sqrt(1-rho.^2)))./(1-qfunc((t1-rho.*tw0)./sqrt(1-rho.^2))))-P,rand);
end

Where for a given t1 we are trying to find tw0 that minimizes the function T0. But for some initial value the qfunc((t1-s1-rho.*tw0+rho.*s2)./sqrt(1-rho.^2)) becomes =1 which starts to provide error in fsolve as i start to get 0/0 form. How can I put a condition in this that helps me do something like this while it searches for tw0 and encounters a 0/0 form .

if qfunc(t1,tw0) < -3
    T0=()
else
    T0=()
end

Answer 1

[Torsten]

T0= fsolve(@(tw0) (exp(-s2.^2./2).*exp(tw0.*s2).*(1-qfunc((t1-s1-rho.*tw0+rho.*s2)./sqrt(1-rho.^2))))-P*(1-qfunc((t1-rho.*tw0)./sqrt(1-rho.^2))),rand);

[Shailee Yagnik]

Hello , the ratio is (1-q())./(1-q())-P

But what u are suggesting is (1-q())-p*(1-q()) which changes my original equation

[Torsten]

I multiplied the equation by the denominator of the first expression which doesn't change the solution.

[Shailee Yagnik]

Yes, I didnt see that, Thanks for helping but u know any different way to do it?

[Torsten]

Why ? Doesn't it solve your problem ?

[Shailee Yagnik]

No, it still gives errors for some initial value of two when the initial conditions(s1,s2,rho) changes. Is there a way to put restrictions on two while fsolve function searches for two?

[Torsten]

Plotting the function which produces problems in the relevant range for "two" might help to get a reasonable initial guess and to identify the cause of errors:

two = linspace(a,b,n);
ftwo = (exp(-s2.^2./2).*exp(tw0.*s2).*(1-qfunc((t1-s1-rho.*tw0+rho.*s2)./sqrt(1-rho.^2))))-P*(1-qfunc((t1-rho.*tw0)./sqrt(1-rho.^2)));
plot (two,ftwo)