How to obtain a set of matrix from another matrix by adding the previous row value along the column to the next row on the same column

Example

a= 2,4;3,4;2 1

the new matrix will be

b= 2,4;3+2,4+4;2+3+2,1+4+4

along the colums

Answer 1

[per isakson]

Is this what you want?

>> cumsum( a, 1 )
ans =
     2     4
     5     8
     7     9

[Bashir Yusuf Bichi]

yes, exactly