Using a loop to create polyfit values for a matrix of numbers

Hi there, I'm trying to create a for loop to run the polyfit function for an array of numbers. The code I am currently using is:

for i=[1:11182];

x(i)=polyfit(Usable_Freq,Usable_Temp(i,:),1);

end

What I need the code to do is for each row of the Usable_Temp matrix, use the same row of Usable_freq and have polyfit run to return the values of this line.Using the above code when I run it, the following error returns: ???

In an assignment A(I) = B, the number of elements in B and I must be the same.

Error in ==> Loop_grad at 3 x(i)=polyfit(Usable_Freq,Usable_Temp(i,:),1);

Any help to resolve this would be greatly appreciated.

Answer 1

[Andrew Newell]

You need to index Usable_Freq also, and polyfit returns two values for a first order fit. Try this:

 N = 11182;
 x = zeros(N,2); % good idea to preallocate
 for i=1:N
 x(i,:)=polyfit(Usable_Freq(i,:),Usable_Temp(i,:),1);
 end

Note the loop syntax: you don't need the square brackets or the semicolon.

[Kris]

That's perfect, works a treat. Thank you very much.

[Alaster McDonach]

Used the very same routine successfully, Thanks