how to plot this data as data-points?

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Otto
Otto 2012-11-5
Hi All,
I have written a code to estimate a root of x^10=1 using modified regula falsi. My code is working pretty well now but I want to plot ea versus iter variable and xr versus iter variable as data-points but there is a problem about this. In my workspace, iter,ea and xr appear only as their last values. I want to see their previous values too. Because of this I can't plot a data-point figure point by point.
Here is my code;
f=@(x)x^10-1;
xl=0;
xu=1.3;
xr = xu;
es=0.01;
fl=f(xl);
fu=f(xu);
iter=0;
iu = 0;
il = 0;
fprintf('\n\n%10s\t%10s\t%10s\t%10s\t%10s\t%10s\t\t%10s\t%10s\n',...
'iter','xl','xu','f(xl)','f(xu)','xr','f(xr)','ea')
fprintf([' ',repmat('-',1,92),'\n'])
while 1
xrold = xr;
xr = xu - fu*(xl-xu)/(fl-fu);
fr = f(xr);
iter=iter+1;
if xr<0
elseif xr>0
ea=abs((xr-xrold)/xr)*100;
end
test = fl*fr;
if test<0
xu = xr;
fu = f(xu);
iu = 0;
il = il+1;
if il>=2
fl=fl/2;
end
elseif test>0
xl=xr;
fl=f(xl);
il=0;
iu=iu+1;
if iu>=2
fu=fu/2;
end
else
ea=0;
end
if ea<es
break
end
fprintf('%10.2i\t%10.7f\t%10.7f\t%10.7f\t%10.7f\t%10.10f\t%10.7f\t%10.4f\t\n',...
iter,xl,xu,f(xl),f(xu),xr,f(xr),ea)
end
fprintf('\n\n')
ModFalsePos=xr;
What would you recommend for this situation?
I'll appreciate for any help.
Thanks Already!

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采纳的回答

Walter Roberson
Walter Roberson 2012-11-6
In the loop, before the "end",
saved_iter(iter) = iter;
saved_ea(iter) = ea;
saved_xr(iter) = xr;
Then after the loop, you can plot saved_iter vs saved_ea and so on.
  1 个评论
Otto
Otto 2012-11-6
Thanks for your help, I have a last question. With this code, I can see the iterations between number 01 and number 11 but I want to see the initial values,i.e 00'th iteration, and the final iteration, ie 12'th iteration, how can I do this? what would you recommend for that? I have only 1 hour to complete this project, so time is running out, I will appreciate for any help. Thank you again!

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