MATLAB: Array indices must be positive intergers or logical values – not sure why i am getting this error message. same code worked for a friend of mine.

#errormessagehelpMATLAB

clf reset 
x=0:0.1:1;
y=[0.9,6.9,31.6,21.5,34.4,68.2,66.4,114.9,155.9,199.3,209.6];
p1=polyfit(x,y,1);
% the code below calculates the r2 values. You can just copy and paste this
% code after your polyfit to find r2 (as long as you use x,y and p1)  
% The polyval function evaluates the equation of the fit at the values of x. 
yhat_1=polyval(p1,x);
% coefficient of determination 
r2=(sum((y-mean(y)).^2)-sum((y-yhat_1).^2))/sum((y-mean(y)).^2);
fprintf('fit y=%.2fx%+.2f \nR2=%.2f\n', p1(1), p1(2),r2);

Best Answer

Read about clear. When you feel you are done with your previous code, then you can clear all your workspace variables and then run the fresh code. It looks there might be a variable conflict earlier when there was error.
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