!-----------------------------------------------------------------------------------------------------------------------------------
! This file is part of ReMKiT1D.
!
! ReMKiT1D is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as
! published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
!
! ReMKiT1D is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
!
! You should have received a copy of the GNU General Public License along with ReMKiT1D. If not, see <https://www.gnu.org/licenses/>.
!
! Copyright 2023 United Kingdom Atomic Energy Authority (stefan.mijin@ukaea.uk)
!-----------------------------------------------------------------------------------------------------------------------------------
module cvode_integrator_class
!! author: Stefan Mijin
!!
!! Contains an Sundials CVODE integrator class
use data_kinds ,only: rk ,ik
use god_objects ,only: Object
use runtime_constants ,only: debugging, assertions, assertionLvl
use assertion_utility ,only: assert, assertIdentical, assertPure
use modeller_surrogate_class ,only: ModellerSurrogate
use variable_container_class ,only: VariableContainer
use modeller_class ,only: Modeller
use integrator_abstract_class ,only: Integrator
use support_types ,only: IntArray ,RealArray ,LogicalArray, StringArray
use mpi_controller_class ,only: CommunicationData,MPIController
use timestep_controller_abstract_class ,only: TimestepController
use support_functions
use status_printing
use, intrinsic :: iso_c_binding
use mpi_f08
use fcvode_mod ! Access CVode
use fsundials_core_mod
use fnvector_parallel_mod
use fsunlinsol_spgmr_mod
implicit none
private
type ,public :: CVODEOptions
integer(ik) :: bbdmukeep !! BBD preconditioner size of kept upper diagonal band
integer(ik) :: bbdmlkeep !! BBD preconditioner size of kept lower diagonal band
integer(ik) :: bbdmldq !! BBD preconditioner size of lower differentiation stencil band
integer(ik) :: bbdmudq !! BBD preconditioner size of upper differentitation stencil band
real(rk) :: reltol !! Linear solver relative tolerance
real(rk) :: abstol !! Linear solver absolute tolerance
integer(ik) :: maxRestarts !! Maximum number of GMRES restarts
logical :: amMethod = .false.!! True if using Adams Moulton (default is BDF)
integer(ik) :: maxOrder !! Maximum order of method
logical :: stabLimitDet = .false. !! True if using stability limit detection
integer(ik) :: maxInternalSteps = 500 !! Maximum number of internal steps
real(rk) :: maxTimestep = 0.d0!! Maximum timestep size
real(rk) :: minTimestep = 0.d0 !! Minimum timestep size
real(rk) :: startingTimestep = 0.0d0 !! Starting timestep (if <0 then chosen by CVODE)
end type CVODEOptions
type ,public ,extends(Integrator) :: CVODEIntegrator
type(c_ptr) ,private :: sunctx !! Sundials context
type(SUNLinearSolver) ,pointer ,private :: sunls !! Sundials linear solver pointer
type(N_Vector) ,pointer ,private :: sunVecY, sunVecYDot !! Solution and RHS sundials vector objects
type(c_ptr) ,private :: cvode !! CVODE solver context
type(SUNMatrix) ,pointer ,private :: sunmat !! Sundials matrix (will be nulled)
real(c_double) ,pointer ,dimension(:) ,private :: rhsVec,yVec !! Pointers used for accessing the underlying N_Vectors
type(VariableContainer) ,allocatable ,private :: bufferRHS ,bufferY !! ReMKiT1D variable containers corresponding to the RHS and solutions - enable derivation and communication calls
real(rk) ,allocatable ,dimension(:) ,private :: copyBufferVals !! Buffer for moving data between the C pointers and the ReMKiT1D variable containers
type(StringArray) ,allocatable ,dimension(:) ,private :: evolvedVars !! List of variables evolved by this solver
type(MPI_Comm) ,private :: mpiComm !! MPI communicator object needed by some CVODE routines
integer(ik) ,private :: numProcs !! Number of processes needed for initialising the number of variables/equations in CVODE
type(CVODEOptions) ,private :: options
character(:) ,allocatable ,private :: integratorName !! Integrator named used in printing
contains
procedure ,public :: affect => integrateCVODE
procedure ,public :: init => initCVODEIntegrator
final :: finalizeCVODEIntegrator
end type CVODEIntegrator
!-----------------------------------------------------------------------------------------------------------------------------------
!-----------------------------------------------------------------------------------------------------------------------------------
interface
!-----------------------------------------------------------------------------------------------------------------------------------
module subroutine integrateCVODE(this,manipulatedModeller,outputVars,inputVars)
!! Implementation of abstract manipulate routine for the case of Runge-Kutta integrator
class(CVODEIntegrator) ,intent(inout) :: this
class(ModellerSurrogate) ,intent(inout) :: manipulatedModeller !! Modeller to be used in callbacks during integration
class(VariableContainer) ,intent(inout) :: outputVars !! VariableContainer object to store the integration output
class(VariableContainer) ,intent(in) :: inputVars !! VariableContainer object housing input data for the integration routine
end subroutine integrateCVODE
!-----------------------------------------------------------------------------------------------------------------------------------
module subroutine initCVODEIntegrator(this,mpiCont,options,modelList,termGroups,&
evolvesTimeVar,dtController,initialTimestep,integratorName)
class(CVODEIntegrator) ,intent(inout) :: this
type(CVODEOptions) ,intent(in) :: options !! Options object containing CVODE options
type(MPIController) ,intent(in) :: mpiCont !! MPI Controller used to initialise the sundials context
integer(ik) ,optional ,dimension(:) ,intent(in) :: modelList !! List of models this integrator will be responsible for
type(IntArray) ,optional ,dimension(:) ,intent(in) :: termGroups !! Term groups this integrator is responsible for - should conform with modelList
logical ,optional ,intent(in) :: evolvesTimeVar !! Set to true if this integrator is allowed to change the "time" varible (if present in passed variable container)
class(TimestepController) ,optional ,intent(in) :: dtController !! User-supplied timestep controller object
real(rk) ,optional ,intent(in) :: initialTimestep !! Default timestep
character(*) ,optional ,intent(in) :: integratorName !! Name of integrator used in printing
end subroutine initCVODEIntegrator
!-----------------------------------------------------------------------------------------------------------------------------------
impure elemental module subroutine finalizeCVODEIntegrator(this)
type(CVODEIntegrator) ,intent(inout) :: this
end subroutine finalizeCVODEIntegrator
!-----------------------------------------------------------------------------------------------------------------------------------
end interface
!-----------------------------------------------------------------------------------------------------------------------------------
end module cvode_integrator_class
!-----------------------------------------------------------------------------------------------------------------------------------
