Sort a list by decreasing order : SortD

SortD takes a list as argument.
SortD returns this list sorted by decreasing order.
Input :

SortD([3,4,2])

Output :

[2,3,4]

SortD may have a matrix as argument and in this case, SortD modifies the order of columns by sorting the first matrix row by decreasing order.
Input :

SortD([[3,4,2],[6,4,5]])

Output :

[[4,3,2],[4,6,5]]