MODULE control

  USE shared_data
  USE normalise

  IMPLICIT NONE

  PRIVATE
  PUBLIC :: user_normalisation, control_variables, set_output_dumps

CONTAINS

  SUBROUTINE user_normalisation

    ! Gamma is the ratio of specific heat capacities
    gamma = 5.0_num/3.0_num

    ! Average mass of an ion in proton masses
    ! The code assumes a single ion species with this mass
    mf = 1.2_num

    ! The equations describing the normalisation in LARE
    ! have three free parameters which must be specified by
    ! the end user. 

    ! Magnetic field normalisation in Tesla
    B0 = 1.0_num
    ! Length normalisation in m
    L0 = 1.0_num
    ! Density normalisation in kg / m^3
    RHO0 = 1.0_num

  END SUBROUTINE user_normalisation



  SUBROUTINE control_variables

    ! Set the number of gridpoints in x and y directions
    nx_global = 512
    ny_global = 512
    nz_global = 512

    ! Set the maximum number of iterations of the core solver before the code
    ! terminates. If nsteps < 0 then the code will run until t = t_end
    nsteps = -1

    ! The maximum runtime of the code
    t_end = 20.0_num

    ! Shock viscosities as detailed in manual - they are dimensionless
    visc1 = 0.0_num
    visc2 = 0.0_num
    ! Real viscosity expressed as the inverse Reynolds number
    visc3 = 0.0_num

    ! Set these constants to manually
    ! override the domain decomposition.
    ! If either constant is set to zero
    ! then the code will try to automatically
    ! decompose in this direction
    nprocx = 0
    nprocy = 0
    nprocz = 0

    ! The length of the domain in the x direction
    x_start = 0.0_num
    x_end = 10.0_num*pi
    ! Should the x grid be stretched or uniform
    x_stretch = .FALSE.

    y_start = 0.0_num
    y_end = 10.0_num*pi
    y_stretch = .FALSE.

    z_start = 0.0_num
    z_end = 10.0_num*pi
    z_stretch = .FALSE.

    ! Turn on or off the resistive parts of the MHD equations
    resistive_mhd = .TRUE.

    ! The background resistivity expressed as the inverse Lundquist
    ! number
    eta_background = 5.0e-4_num

    ! The critical current for triggering anomalous resistivity
    ! and the resistivity when above the critical current
    ! The resistivity is expressed as the inverse Lundquist number
    j_max = 0.0_num
    eta0 = 0.0_num

    ! Turn on or off the Braginskii thermal conduction term in
    ! the MHD equations   
    conduction = .FALSE. 
    ! Apply a flux limiter to stop heat flows exceeding free streaming limit
    ! this is an experimental feature
    heat_flux_limiter = .FALSE.
    ! Fraction of free streaming heat flux used in limiter
    flux_limiter = 0.01_num
    
    ! Use radiation as specified in SUBROUTINE rad_losses in src/core/conduct.f90   
    radiation = .FALSE.
    ! Use coronal heating as specified in SUBROUTINE heating in src/core/conduct.f90
    coronal_heating = .FALSE.       
    
    ! Remap kinetic energy correction. LARE does not
    ! perfectly conserve kinetic energy during the remap step
    ! This missing energy can be added back into the simulation
    ! as a uniform heating. Turning rke to true turns on this
    ! addition
    rke = .FALSE.

    ! The code to choose the initial conditions. The valid choices are
    ! IC_NEW - Use set_initial_conditions in "initial_conditions.f90"
    !         to setup new initial conditions
    ! IC_RESTART - Load the output file with index restart_snapshot and
    ! use it as the initial conditions
    initial = IC_NEW
    restart_snapshot = 1

    ! If cowling_resistivity is true then the code calculates and
    ! applies the Cowling Resistivity to the MHD equations     
    ! only possible if not EOS_IDEAL
    cowling_resistivity = .FALSE.

    ! Set the boundary conditions on the four edges of the simulation domain
    ! Valid constants are
    ! BC_PERIODIC - Periodic boundary conditions
    ! BC_OPEN - Reimann characteristic boundary conditions
    ! BC_OTHER - User boundary conditions specified in "boundary.f90"
    xbc_min = BC_PERIODIC
    xbc_max = BC_PERIODIC
    ybc_max = BC_PERIODIC
    ybc_min = BC_PERIODIC
    zbc_min = BC_PERIODIC
    zbc_max = BC_PERIODIC

    ! set to true to turn on routine for damped boundaries
    ! these routines are in boundary.f90 and you should check these
    ! actually do what you want.
    damping = .FALSE.

    ! Set the equation of state. Valid choices are
    ! EOS_IDEAL - Simple ideal gas for perfectly ionised plasma
    ! EOS_PI - Simple ideal gas for partially ionised plasma
    ! EOS_ION - EOS_PI plus the ionisation potential 
    ! N.B. read the manual for notes on these choices
    eos_number = EOS_IDEAL
    ! EOS_IDEAL also requires that you specific whether
    ! the gas is ionised or not. Some startified atmospheres
    ! only work for neutral hydrogen for example
    ! For fully ionised gas set .FALSE.
    ! For neutral hydrogen set .TRUE.
    ! This flag is ignored for all other EOS choices.
    neutral_gas = .FALSE.

  END SUBROUTINE control_variables



  SUBROUTINE set_output_dumps

    ! The output directory for the code
    data_dir = "Data"

    ! The interval between output snapshots. If SI_Input is true
    ! Then this is in seconds
    dt_snapshots = 10.0_num

    ! dump_mask is an array which specifies which quantities the
    ! code should output to disk in a data dump.
    ! The codes are
    ! 1  - rho
    ! 2  - energy
    ! 3  - vx
    ! 4  - vy
    ! 5  - vz
    ! 6  - bx
    ! 7  - by
    ! 8  - bz
    ! 9  - temperature
    ! 10 - pressure
    ! 11 - cs (sound speed)
    ! 12 - parallel_current
    ! 13 - perp_current
    ! 14 - neutral_faction
    ! 15 - eta_perp
    ! 16 - eta
    ! 17 - jx
    ! 18 - jy
    ! 19 - jz
    ! If a given element of dump_mask is true then that field is dumped
    ! If the element is false then the field isn't dumped
    ! N.B. if dump_mask(1:8) not true then the restart will not work
    dump_mask = .FALSE.
    dump_mask(1:9) = .TRUE. 
    IF (eos_number /= EOS_IDEAL)  dump_mask(14) = .TRUE. 
    IF (cowling_resistivity)  dump_mask(15) = .TRUE. 
    IF (resistive_mhd)  dump_mask(16) = .TRUE. 

  END SUBROUTINE set_output_dumps

END MODULE control