SimpleDipoleProblem/initialise.f90 at main · asdwerte1/SimpleDipoleProblem · GitHub

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module initialise
!------------------------------------------------------------------------------------------!
!------Module to initialise problem by allowing user to select desired N, direction of-----!
!------magnetic moments and whether to run in series or parallel.--------------------------!
!------------------------------------------------------------------------------------------!
  use physical_constants

  implicit none

  contains

  !initialisation subroutine
  recursive subroutine init(mag_vector, coords, N, sORp)

    real(kind=dp), dimension(3), intent(out) :: mag_vector

    real(kind=dp), dimension(:), allocatable, intent(out) :: coords

    integer, intent(out) :: N

    character :: mag_direction

    character, intent(out) :: sORp

    !If this read statement is uncommented, will be used to read in values for N,
    !mag_direction and sORp from bash script rather than them being entered at run time.
    !For this must also comment out all other read statements in this module
    !read (*,*) N, mag_direction, sORp

    !Open a file which can be 3D plotted (e.g. with gnuplot) to
    !display the ellipsoid of points (or cube should the dimensions be smaller than the
    !ellipsoid radii.
    !open(unit=unit1, file="ellipsoid.txt", iostat=istat)
    !if(istat/=0) stop "Error opening ellipsoid.txt"

    !Section allows user to choose value for N
    print *, "-----------------------------------------------------------------"

    print *, "Enter a value for N. The total number of dipoles will be", &
             " N cubed, such that they form a cube of side N dipoles."

    read(*,*) N

    !check to make sure N is > 0
    if(N<=0)then

      print *, "ERROR: N may not be less than or equal to zero."

      print *, coords

      call init(mag_vector, coords, N, sORp)

    else

      print *, "N is set to:", N

    endif

    !Section allows user to choose direction of magnetic dipole moment
    print *, "-----------------------------------------------------------------"

    print *, "Please choose the direction of the magnetic moment of each", &
             " dipole"

    print *, "Type 'x', 'y' or 'z' to choose the direction. Or type 'r' to", &
             " restart."

    read(*,*) mag_direction

    if(mag_direction == "x")then

      mag_vector = [1.0_dp, 0.0_dp, 0.0_dp]

    elseif(mag_direction == "y")then

      mag_vector = [0.0_dp, 1.0_dp, 0.0_dp]

    elseif(mag_direction == "z")then

      mag_vector = [0.0_dp, 0.0_dp, 1.0_dp]

    elseif(mag_direction == "r")then

      call init(mag_vector, coords, N, sOrp)

    else

      print *, mag_direction, " is not a valid input."

      call init(mag_vector, coords, N, sORp)

    endif

    print *, "The unit vector for the magnetic moment of each dipole is"

    print *, mag_vector

    !check to see if coords has already been allocated
    !This happens if N was given a not allowed value (<=0)
    if(allocated(coords))then

      deallocate(coords)

    endif

    !allocate size of coordinate arrays
    allocate(coords(1:N))

    !set possible x, y and z coordinates
    do i = 1, N

      coords(i) = real(i,dp) * l

    enddo

    !initialise ellipsoid
    call ellipsoid(N, l, ellipCent)

    print *, "-----------------------------------------------------------------"

    print *, "Ellipsoid is centred on the coordinates x = y = z with x,y,z ="

    print *, ellipCent

    print *, "-----------------------------------------------------------------"

    print *, "Select whether to calculate in serial('s') or parallel('p').", &
             " Or type 'r' to restart."

    read(*,*) sORp

    if(sORp == "s")then

      print *, "Running in serial."

    elseif(sORp == "p")then

      print *, "Running in parallel."

    elseif(sORp == "r")then

      call init(mag_vector, coords, N, sORp)

    else

      print *, sORp, "is not a valid input."

      call init(mag_vector, coords, N, sORp)

    endif

  endsubroutine init

  !Subroutine to create the ellipsoid such that it is centered on the centre of the cube
  !of dipoles produced.
  subroutine ellipsoid(N, l, center)

    real(kind=dp), intent(in) :: l

    real(kind=dp) :: halfway

    integer, intent(in) :: N

    !centre point of ellipsoid, centred on the centre of the cube of dipoles
    real(kind=dp), intent(out) :: center

    !calculate halfway point between lowest and highest coordinate points
    halfway = (N*l) - l

    !set central point of the ellipsoid
    center = (halfway / 2.0_dp) + l

  endsubroutine ellipsoid

endmodule initialise