MATLAB: Numerical solution

Question

Hello

I´m working on a numerical solution for an equation. Therefore I wrote the following function:

function test(dBL,i)

 for n=1:i
    BL=0;

while (1+cos(BL)*cosh(BL))*(1+cos(BL+dBL)*cosh(BL+dBL))>0

   BL=BL+dBL;
fc=1+cos(BL)*cosh(BL);
end

vfc(n,1)=fc;

vBL(n,1)=BL;

end

vfc

vBL

end

My aim is that the matlab function produce as many solutions as n and the important output is vBL, which is a vector with the solutions.

I want the while loop to start with BL=0 for n=1, but for n=2 I want the loop to start with the last BL from the previous while loop and so on. Anybody can help??

Thanks in advance

Answer 1

Unless I misunderstood something, I think all you need to do is change:

BL = 0;

to

if n == 1
    BL = 0;
end

Then for n > 1, "BL" will be whatever value it was at the end of the previous iteration.

In your case (now that I am looking at it more closely), if "BL" starts off as the same value as the previous iteration, then the "while" loop probably will not execute... since "BL" and "dBL" are not changing, (1+cos(BL)*cosh(BL))*(1+cos(BL+dBL)*cosh(BL+dBL))>0 will also not change. Should that expression be some sort of function of "n" as well?