I use this command from the Mathematica documentation center
Export["1.mat", {"t" -> {{1,2,3}},"u" -> {{4,5,6}}}, "LabeledData"]
to save data as mat file with two variables t and u, and it does not work. The file is empty! The command Export["1.mat",{{1,2,3}}] works fine. How to solve this problem? I'd like to save in single file plenty variables. I am using Mathematica 7.