Computing the mean over 3 numbers in a matrix

I have a matrix with dimensions of 5000*51. I want to find the average over each 3 numbers and finally I have a matrix of 5000 * 17.

[Image Analyst]

Do you want a moving mean where the window of 3 moves over one row, or one column, each time, or do you want the window to move in jumps of 3? Do you want 3 in the same row to be averaged? Or do you want the 3 to be in the same column? Which way do you want the mean to go????

Answer 1

[KSSV]

Let A be your matrix.

[m,n] = size(A) ;
B = reshape(A,m,3,[]) ; 
C = mean(B,2) ;
iwant = reshape(C,m,[]) ;

Answer 2

[Chunru]

A = rand(5000, 51);  % your data
A1 = reshape(A, [5000 3 17]);  % reshape the 51 element by 3x17 array
meanA = mean(A, 2);  % Mean along 2nd dimension

[mohamad shirgholami]

meanA = mean(A1, 2);

[mohamad shirgholami]

thanks for your answer.