Matrix row norm : rownorm rowNorm

rownorm (or rowNorm) takes as argument a matrix A = a_{j, k}.
rownorm (or rowNorm) returns $\max_{k}^{}$($\sum_{j}^{}$| a_{j, k}|).
Input :

rownorm([[1,2],[3,-4]])

or

rowNorm([[1,2],[3,-4]])

Output :

7

Indeed : max(1 + 2, 3 + 4) = 7