mapAboveDiagonalmapAboveDiagonal1 = With[{dim = Dimensions[#2]},
MapAt[#, #2, Join @@ Table[{i, j}, {i, dim[[1]]}, {j, i, dim[[2]]}]]] &
or
mapAboveDiagonal2 = MapAt[#, #2,
SparseArray[UpperTriangularize[
ConstantArray[1, Dimensions[#2]]]]["NonzeroPositions"]]&;
mm = Array[m, {5, 5}];
Row[MatrixForm /@ {mm, mapAboveDiagonal[fmapAboveDiagonal1[f, mm]}]
mapAboveDiagonal = MapAt[#, #2,
SparseArray[UpperTriangularize[
ConstantArray[1, Dimensions[#2]]]]["NonzeroPositions"]]&;
mm = Array[m, {5, 5}];
Row[MatrixForm /@ {mm, mapAboveDiagonal[f, mm]}]
mapAboveDiagonal1 = With[{dim = Dimensions[#2]},
MapAt[#, #2, Join @@ Table[{i, j}, {i, dim[[1]]}, {j, i, dim[[2]]}]]] &
or
mapAboveDiagonal2 = MapAt[#, #2,
SparseArray[UpperTriangularize[
ConstantArray[1, Dimensions[#2]]]]["NonzeroPositions"]]&;
mm = Array[m, {5, 5}];
Row[MatrixForm /@ {mm, mapAboveDiagonal1[f, mm]}]