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Why do I get NaN result?

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Ludvig Hultman
Ludvig Hultman on 12 Oct 2020
Closed: MATLAB Answer Bot on 20 Aug 2021
When I'm using the steepest descent method I have a hard time getting the result on the x:cordinate.
In the code below, the issue arises in "gradf". Can someone help me?
n=0; %initialize iteration counter
eps=1; %initialize error
a=0.04; %set iteration parameter
x=[-1;-1]; %set starting value
%Computation loop
while eps>0.5e-4&n<100
gradf=[3*x(1)^2+0.8*x(1)+2.8*x(2); 2.8*(x(1))+2.7*(x(2))^2-1.1]; %gradf(x)
eps=abs(gradf(1))+abs(gradf(2)); %error
y=x-a*gradf; %iterate
x=y; %update x
n=n+1; %counter+1
n,x,eps, %display end values

Answers (1)

Sudhakar Shinde
Sudhakar Shinde on 12 Oct 2020
Values within gradf function for n=32 becomes infinite ('inf') and hence results are NAN (Not a number).

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