The integrator naming conventions:

*.def = definition file
*.f   = Fortran 77 source code
*.f90 = Fortran 90 source code
*.c   = C source code

atm_* = off-the-shelf integrators, adapted to work with KPP
        use the native full linear algebra
	useful for providing reference solutions
	
kpp_* = off-the-shelf integrators, using the KPP sparse linear algebra	
        very efficient, useful for production runs
	
plain names = original integrators
        either use the KPP sparse linear algebra, or provide
	explicit solutions	
	
*_ddm = direct decoupled method
        integrate for both the concentrations and their sensitivities
	implements the forward and the tangent linear models together