how to see previous results while tabulating?

Hi All,

I've written a code using Newton-Raphson algorythm but i have problems with tabulating. I want to tabulate my results in a form which first column corresponds "it_no"(iteration number),second column corresponds "x", third column corresponds "f(x)". But I'm only getting the last results of iteration, i.e it_no 9;

Here is the code

f=@(x)x^5-x^4+(2*x^3)-(3*x^2)+x-4
dfdx=@(x)(5*x^4)-(4*x^3)+(6*x^2)-(6*x)+1
x0=5
x=x0
it_no=0
while 1
    f(x)
    it_no=it_no+1
    xprev=x
    x=xprev-(f(x)./dfdx(x))
    if f(x)<10^-4
        break
    end  
end
fprintf('\n\n%18s%18s%18s\n','it_no','x','f(x)')
fprintf(' %17.0f\t %17.7f\t %17.7f\t\n',[it_no,x,f(x)])

I want to see all results from first iteration to last iteration. Anyway to see previous results in my table?

I'll appreciate for any help

Thanks Already!

Answer 1

[John Petersen]

Change where you put your print statements to see running total.

fprintf('\n\n%18s%18s%18s\n','it_no','x','f(x)');
while 1
    it_no=it_no+1;
    xprev=x;
    x=xprev-(f(x)./dfdx(x));
    if f(x)<10^-4;
        break
    end  
    fprintf(' %17.0f\t %17.7f\t %17.7f\t\n',[it_no,x,f(x)]);
end

For faster code, you could vectorize it, but it would print after the loop not while running in the loop.