i this talk i will discuss non-commutative donaldson-thomas invariants for a class of toric calabi-yau manifolds. the generating function of these invariants is computed by a crystal melting model, which is determined by the ``tropical limit'' of the coamoeba of the newton polynomial of the toric diagram. in the thermodynamic limit, the limit shape of the crystal gives amoeba of the mirror calabi-yau manifold. if time allows, i will also discuss the wall crossing of donaldson-thomas invariants.\\ talk time runs to 10:30 am.