You can just round the result, and then they are the same number.
Total[ E^Total[E^(Round[list, 10.^-6]/t)]
(* 4 E^(-0.683013/t) + 3 E^(-0.183013/t) +
2 E^(0.183013/t) + E^(
0.683013/t) *)
The Exp
and Round
function are listable, so you don't need an explicit call to Sum
. But if you wanted one,
Sum[ E^(Round[list[[k]], 10.^-6]/t), {k, Length[list]}]
Edit You can also use SetPrecision
Total@Exp[ SetPrecision[list, 6]/t]
(* 4 E^(-0.683013/t) + 3 E^(-0.183013/t) +
2 E^(0.183013/t) + E^(0.683013/t) *)
But I don't see an equivalent to SameTest
for Plus