MATLAB: Saving regula-falsi iterations

while loop

Hi everybody, I would like to save the iterations of X variable into a vector. I can only get the final resul, that is the solution equation, while my goal is that to obtain the whole series.
ex: x=[x1,x2,…,xn].
function [x,iter]= RegulaFalsi(f,a,b,ep,itermax)
x0=a;
x1=b;
iter=0; %number iterations
x=b;
while (abs(f(x)) > ep) && (iter<itermax)
        x=x0-((f(x0)*(x1-x0))/(f(x1)-f(x0))); %intersection X axis
    if (f(x)*f(x0)>0)
        x0=x;
        x1=b;
    else (f(x)*f(b)>0)
        x1=x;
        x0=a;
    end
    if iter==itermax
        disp('Maximum number of iterations reached')
    end
    iter=iter+1;
end

Best Answer

Hi,
I would suggest you to use an array to store the value of x in every iteration. You can accomplish this using the following code snippet:
function [x,iter]= RegulaFalsi(f,a,b,ep,itermax) 
  x0=a; 
  x1=b; 
  iter=0; %number iterations 
  x=b; 
  i = 1; 
  x = zeros(1,itermax); 
  x(i)=b; 
  z=x(i); 
  while (abs(f(z)) > ep) && (iter<itermax) 
     x(i)=x0-((f(x0)*(x1-x0))/(f(x1)-f(x0))); %intersection X axis 
     z=x(i); 
     i= i+1; 
     if (f(z)*f(x0)>0) 
        x0=z; 
        x1=b; 
     else (f(z)*f(b)>0) 
        x1=z; 
        x0=a; 
     end 
     iter=iter+1;
     if iter==itermax 
        disp('Maximum number of iterations reached') 
     end  
  end 
end
Another alternative would be to make use of the following code for "Regula-Falsi Method" provided in MATLAB Central:
https://in.mathworks.com/matlabcentral/fileexchange/45859-regula-falsi-method?focused=3813714&tab=function
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