Before revision:  DAT breaks an original global problem into many parallel tree-structured small local problems, which can be effectively solved. All such local solutions are then linked together to form a global solution by solving small Dirac assisted linking problemswith an inherent tree structure.
After revision:  DAT breaks an original global problem into many parallel tree-structured small local problems, which are linked together to form a global solution by solving small Dirac assisted linking problemswith an inherent tree structure.