round(M) rounds M to the nearest integer.

The round(M) function rounds element-wise to the nearest integer of M.  The result, R, is formed as R[i,j] = round(M[i,j]).

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$M≔\mathrm{Matrix}\left(2\,3\,'\mathrm{fill}'=-3.6\right)\:$

$\mathrm{round}\left(M\right)$

$\left[\begin{array}{ccc}\mathrm{-4}& \mathrm{-4}& \mathrm{-4}\\ \mathrm{-4}& \mathrm{-4}& \mathrm{-4}\end{array}\right]$