Matrix Average beside the numbers

After creating a matrix of order MxM it will then output a new matrix in which each element is calculated from the original matrix by finding the average of each element adjacent (horizontally, vertically and diagonally) to the original element including the element itself. Each matrix element in the output should have 2 decimal places.

For example M=3 then matrix is [1,2,3;6,5,4;7,8,9]

element ?(1,1) = (1 + 2 + 6 + 5)/ 4 = 3.5

?(1,2) = (1 + 2 + 3 + 6 + 5 + 4) /6 = 3.5

Answer 1

[Andrei Bobrov]

M =[ 1     2     3
     6     5     4
     7     8     9];
 
X = conv2(M,ones(3),'same')./conv2(ones(3),ones(3),'same');