Incorrect dimensions for matrix multiplication
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%Load the data
load data.mat;
%Extracting first 500 points
z = [y(1:500) u(1:500)];
%Plotting the data
figure(1)
idplot(z);
%Using sampling interval of 80ms
figure(1)
idplot(z, 1:500, 0.08);
%Reserving the remaining data
zr = [y(501:1000) u(501:1000)];
%Removing constant levels and making data zero mean
z = dtrend(z);
zr = dtrend(zr);
%Loss function calaculation
V = arxstruc(z, zr, struc(2,2, 1:10));
value = V(1,:);
nk_value = min(value);
V = arxstruc(z, zr, struc(1:5, 1:5, 3));
%Searching for settled-in point
nns = selstruc(V);
i=1;
%Model structure
for na = 1:5
for nb = 1:5
val(i,:) = na+nb;
th = arx(z,[na, nb, 3]);
mse(i,:) = [th.Report.Fit.MSE];
a = th.a;
b = th.b;
ysim = idsim(zr(:, 2), th);
i=i+1;
matx = [val mse];
A = matx;
[A1u,~,idx] = unique(A(:,1));
MinVals = accumarray(idx, A(:,2), [], @(x)min(x));
Result = [A1u, MinVals];
m_one = Result(:,1);
m_two = Result(:,2);
figure(2)
plot(m_one, m_two)
title('Complexity vs Loss Function');
xlabel('Complexity');
ylabel('Loss Function');
end
end
%A-parameter and B-parameter
th = arx(z,[4 4 3]);
th = sett(th, 0.08);
present(th);
A=th.a
B=th.b
%Least Square Estimation
i = 1;
for k=6:length(z)
phi(i,1:5) = [-z(k-1,1) -z(k-2,1) z(k-3,2) z(k-4,2) z(k-5,2)];
i = i+1;
end
Y = z(6:end,1);
L = inv(phi'*phi)*phi*Y;
Getting an error that says 'Incorrect dimensions for matrix multiplication.'
Can anyone explain why this error comes up?
1 个评论
Walter Roberson
2019-3-7
This code requires idplot(), which existing in the MATLAB 3 (1987) to MATLAB 5 (1997) timeframe and which was removed from MATLAB before R13. A copy of the source appears to be at http://research.jisao.washington.edu/vimont_matlab/System/idplot.html
回答（1 个）
Adarsh Ghimire
2019-3-7
编辑：Adarsh Ghimire
2019-3-7
0 个投票
L = inv(phi ' * phi ) * phi' * Y;
your phi matrix dimension has to transposed to multiply with y. As i went through your code, I found that
dimensions:
phi = (z-6) x 6
and y = (z-6)x1
so transposing your phi and multiply with y will get you 6x1 matrix which can multiply with inverse result of 6x6 so you get 6x1 matrix as your L.
6 个评论
Gautami Golani
2019-3-7
Adarsh Ghimire
2019-3-7
can you tell which at which line is that multiplication error ?
Gautami Golani
2019-3-7
Adarsh Ghimire
2019-3-7
编辑：Adarsh Ghimire
2019-3-7
Use debugging at that line at determine the size of those phi and y, check if the dimensions are well matching for multiplication to be carried.
It may be due to degenrative nature of phi' x phi matrix, so try this one.
L = pinv(phi'*phi)*phi'*Y;
Gautami Golani
2019-3-8
Adarsh Ghimire
2019-3-9
then you manage the dimension
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