??? Attempted to access G(2); index out of bounds because numel(G)=1.

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Bennie
Bennie on 8 Dec 2011
Hello, I am trying to do the below calculation and I keep getting this error. I need it to compare the difference of subsuquent calculations and repeat the loop until their difference is less than 0.0001. clear all; R=2.4; P=.1; eta= 10e-19; k=1; G(k)= R* eta /.1 Q=.5 k=k+1 while(G(k) - G(k- 1) > .0001) G(k) = G(k+1)*{1-(G(k)+1)/(G(k+1)+G(k))}+ Q k=k+1;
end
??? Attempted to access G(2); index out of bounds because numel(G)=1.
Error in ==> homework4 at 9 while(G(k) - G(k- 1) > .0001)

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Accepted Answer

Robert Cumming
Robert Cumming on 8 Dec 2011
do you know how to bebug? highlight the line before the while loop in editor and hit F12 on keyboard. Run your code. Inspect your variables - see if you can understand the error message.
As this is homework I'm not going to tell you the answer - this is an attempt to guide you to find the answer yourself - you will learn more that way...

More Answers (2)

Sven Schoeberichts
Sven Schoeberichts on 8 Dec 2011
You are trying to access G(k+1) before it exists
clear all;
R = 2.4;
P = 0.1;
eta = 10e-19;
k = 1;
G( k ) = R * eta / 0.1;
Q = 0.5;
k = k + 1;
while( G(k) - G(k-1) > 0.0001 )
G(k) = G(k+1)*{1-(G(k)+1) / (G(k+1)+G(k))}+ Q;
k = k + 1;
end
  1 Comment
Bennie
Bennie on 8 Dec 2011
I kind of new that: I think the function as given in the problem is flawed. Thanks for your help.

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Wayne King
Wayne King on 8 Dec 2011
Hi, You should format your code so that people can read it.
Your problem is that you have G as a scalar:
R=2.4; P=.1; eta= 10e-19;
k=1; G(k)= R* eta /.1;
Then you try to access G(2) in your while statement
k = k+1;
while(G(k)-G(k-1)>0.0001)
but you have never provided a value for G(2). You increment k up to 2 with k = k+1, so your while statement attempts to evaluate G(2)

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