Error: Inner matrix dimensions must agree.

 Size of  Fh and Reh is [15 25] and size of Prh is [1 25]
  for i=1:1:N1
    for j=1:1:length(Dd)
 Nuh(:,i)=((Fh(:,i)/8)*(Reh(:,i)-1000)*Prh(i))/(1+12.7*(Fh(:,i)/8).^(0.5).*(Prh(i).^(2/3))-1);
end
end

How I can overcome the error.

Answer 1

[Jan]

We have to guess what you want to achieve, because all we see is the failing code. If you mention the intention (preferrably in a comment, such that you can read it also, when you try to maintain the code in 2 years), suggesting an improvement is more reliable.

Look at this expression:

(Fh(:,i) / 8) * (Reh(:,i) - 1000) * Prh(i))

This is the multiplication of two [15 x 1] vectors, but this is not allowed (in Matlab and mathematically). What is the wanted output? Either use the elementwise multiplication:

(Fh(:,i) / 8) .* (Reh(:,i) - 1000) * Prh(i))

or transpose the 1st vector:

(Fh(:,i).' / 8) * (Reh(:,i) - 1000) * Prh(i))

The division by / will suffer from the same problem. Again either adjust the array dimensions or use the elementwise operation ./ .

You can solve such problems by your own: Split the complicated command into small blocks and process them one by one:

a = Fh(:,i) / 8;
b = (Reh(:,i) - 1000) * Prh(i);
c = sqrt(Fh(:,i) / 8);  % SQRT is much faster than ^0.5
... etc
d = a * b;
Nuh(:,i) = (d / (1+12.7*c.*(Prh(i).^(2/3))-1);

Now you can check the dimension of the smaller blocks much easier and find problems efficiently.

Note: Inserting spaces around operators increase the readability.