I want to calculate the mean of two rows in matlab

Question

I have a 1028 by 18 matrix in matlab.I want to calculate the mean of 1st and 2nd row by column values,3rd and 4th and so on in Matlab and get a new matrix with the mean values.<

Answer 1

I think what you are looking for is:

x = rand( 1028, 18 );
meanx = ( x(1:2:end,:) + x(2:2:end,:)) / 2;

After running this, meanx will be a [514 x 18] matrix.

The first row of meanx is the average of rows 1 and 2 in x.

The second row of meanx is the average of rows 3 and 4 in x.

The third row of meanx is the average of rows 5 and 6 in x.

EDIT:

If you also want to exclude some of the rows from the averaging procedure based on the value of the first row, then you can add the following:

dx = diff(x(:,1));

goodrows = (dx(1:2:end) == 0);  %find row-pairs for which the first elements match
badrows = ~goodrows;

goodmeans = meanx(goodrows,:)  %average rows with matching first element
badmeans = meanx(badrows,:)    %average rows with non-matching first element