%+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%STUDENTS OF 412 ARE ENTITLED TO USE A VARIATION OF THIS FILE FOR
%THEIR ASSIGNMENT.  IF YOU DO THAT, REPORT THAT FACT ON THE 
%ASSIGNMENT (WRITE : `I USED THE CODE AT CLASS ACCOUNT AS MY BASE CODE')
%YOU MAY WISH, HOWEVER, TO WRITE SOMETHING A BIT MORE SOPHISTICATED
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

%in this file, we try to solve the equation x^3=sin(x)
%using four different fixed point algorithms. 
%rat is the (estimated) ratio between the current error and the previous one. 
%only one iteration is performed. 
%before you use this file, type `n=1'. This will initialize the
%parameters in the code, and will also keep a counter on the number
%of iterations.  the value of rat after one iteration is meaningless.
%note that the solution is around .9


 if n==1
    k=4 ; % k is the number of different fixed point algorithms you run
	  % it is 4 in the current code. if you add more, change k
    x=ones(1,k);    
    error=ones(1,k);
    a=3-cos(1);
 end

% we store in x the old value of x, and in y new value of x, i.e., y=g(x)
%when we are done, we overwrite x by y (for the sake of the new iteration)
%alternatively, you can generate a vector where all the iterative values

y(1)=sin(x(1))^(1/3); 
y(2)=sin(x(2))/x(2)^2; 
y(3)=x(3)-(x(3)^3-sin(x(3)));
y(4)=x(4)-(x(4)^3-sin(x(4)))/a;
%y(5)=asin(x(5)^3); %try that if you wish. do not forget to change k then

%add a few more choices if you wish
%e.g., try to see how Newton's method outperform the competition

rat=(y-x)./error 
%that's it. we now update error and x (anticipating another iteration)
error=y-x; x=y, n=n+1;