Work in progress!
The propagator class
type, extends(algorithm_t), abstract :: propagator_t private class(system_t), pointer, public :: system !< The system using this propagator type(algorithm_iterator_t) :: scf_start !< If the algorithm contains a self-consistency loop, !! we need to save the start of that loop to be able to !! jump back to it. FLOAT, public :: dt !< Physical duration of one time step FLOAT, public :: final_time = M_ZERO !< The final time of the simulation. ! Options related to predictor-corrector propagators logical, public :: inside_scf = .false. !< Indicate whether the system is executing an SCF loop logical, public :: predictor_corrector = .false. integer, public :: scf_count !< Counter for self-consistency iterations integer, public :: max_scf_count !< Maximum number of iterations for self-consistent propagators integer, public :: accumulated_loop_ticks FLOAT, public :: scf_tol !< Tolerance for self-consistent propagators contains ! Below are the list of operations that needs to be implemented procedure :: do_operation => propagator_do_operation !< @copydoc propagator_do_operation procedure :: finished => propagator_finished !< @copydoc propagator_finished procedure :: init_iteration_counters => propagator_init_iteration_counters !< @copydoc propagator_init_iteration_counters procedure :: save_scf_start => propagator_save_scf_start !< @copydoc propagator_save_scf_start procedure :: rewind_scf_loop => propagator_rewind_scf_loop !< @copydoc propagator_rewind_scf_loop end type propagator_t
propagator_t is an extension of
algorithm_t. Therefore, it contains the list of operations, which define the propagator.
The elements of the propagator algorithm are defined as algorithmic operations.
The complete propagation algorithm is then defined by adding each step of the algorithm to the propagator (see the examples).
Note, that at this level, progators are independent of the actual implementation of each step. These have to be implemented within the system, for which the propagator will be applied.
Here, we define the following operations:
! Known propagation operations character(len=ALGO_LABEL_LEN), public, parameter :: & START_SCF_LOOP = 'START_SCF_LOOP', & END_SCF_LOOP = 'END_SCF_LOOP', & STORE_CURRENT_STATUS = 'STORE_CURRENT_STATUS' type(algorithmic_operation_t), public, parameter :: & OP_START_SCF_LOOP = algorithmic_operation_t(START_SCF_LOOP, 'Starting SCF loop'), & OP_END_SCF_LOOP = algorithmic_operation_t(END_SCF_LOOP, 'End of SCF iteration'), & OP_STORE_CURRENT_STATUS = algorithmic_operation_t(STORE_CURRENT_STATUS, 'Store current status')
These operations are general and not bound to a specific propagator, or a specific system. Therefore, they are implemented in the
system_t class. For a discussion, see the section on time propagation.
The class procedures of
propagator_t are those. handling the internal state of the propagator.
Specific propagators are defined as classes extending
propagator_t. The necessary specific algorithmic steps are to be defined in the scope of the module file, containing the extending class.