ODE45 problem. How to change the initial conditions?

Hi. I am still pretty new to Matlab and was wondering if anyone could help me with the following problem.

I have the following function file:

function Sxint = fnc(c)

options = odeset('RelTol', 0.0001);

sol = ode45(@phase,[-1, 1],[0;1],options,c);

xint = 1; p = deval(sol,xint); Sxint = p(1); format short

I have defined all unknown values in different files but I think they are irrelevant for my question anyway.

My initial condition is y(-1)=0 and y'(-1)=1. I have been looking through the documentation here and all the examples have boundary conditions from 0 on(e.g[0, 20]) so I want to know if I have to change my initial conditions relevant to my boundaries or does Matlab do it automatically? Any help would be great as this is urgent.

Thanks, Ben

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency