unit.F90

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!! Copyright (C) 2002-2006 M. Marques, A. Castro, A. Rubio, G. Bertsch
!!
!! This program 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 2, or (at your option)
!! any later version.
!!
!! This program 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 this program; if not, write to the Free Software
!! Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
!! 02110-1301, USA.
!!
 
!
 
#include "global.h"
 
module unit_oct_m
  use global_oct_m
  implicit none
 
  private
  public ::            &
    unit_t,            &
    units_to_atomic,   &
    units_from_atomic, &
    units_abbrev,      &
    operator(*),       &
    operator(/),       &
    operator(**),      &
    sqrt
 
  type unit_t
    ! Components are public by default
    real(real64)      :: factor
    character(len=20) :: abbrev
    character(len=50) :: name
  end type unit_t
 
  interface operator (*)
    module procedure units_multiply
  end interface operator (*)
 
  interface operator (/)
    module procedure units_divide
  end interface operator (/)
 
  interface operator (**)
    module procedure units_pow
  end interface operator (**)
 
  interface units_to_atomic
    module procedure dunits_to_atomic, zunits_to_atomic
  end interface units_to_atomic
 
  interface units_from_atomic
    module procedure dunits_from_atomic, zunits_from_atomic
  end interface units_from_atomic
 
  interface sqrt
    module procedure units_sqrt
  end interface sqrt
 
contains
 
  !-----------------------------------------------
 
  real(real64) elemental pure function dunits_to_atomic(this, val) result(res)
    type(unit_t), intent(in) :: this
    real(real64), intent(in) :: val
 
    res = val*this%factor
 
  end function dunits_to_atomic
 
  !-----------------------------------------------
 
  complex(real64) elemental pure function zunits_to_atomic(this, val) result(res)
    type(unit_t), intent(in) :: this
    complex(real64),        intent(in) :: val
 
    res = val*this%factor
 
  end function zunits_to_atomic
 
  !-----------------------------------------------
 
  real(real64) elemental pure function dunits_from_atomic(this, val) result(res)
    type(unit_t), intent(in) :: this
    real(real64),      intent(in) :: val
 
    res = val/this%factor
 
  end function dunits_from_atomic
 
  !-----------------------------------------------
 
  complex(real64) elemental pure function zunits_from_atomic(this, val) result(res)
    type(unit_t), intent(in) :: this
    complex(real64),   intent(in) :: val
 
    res = val/this%factor
 
  end function zunits_from_atomic
 
  !-----------------------------------------------
 
  character(len=20) pure function units_abbrev(this) result(abbrev)
    type(unit_t), intent(in) :: this
 
    abbrev = this%abbrev
  end function units_abbrev
 
  !-----------------------------------------------
 
  type(unit_t) pure function units_multiply(aa, bb) result(cc)
    type(unit_t), intent(in) :: aa
    type(unit_t), intent(in) :: bb
 
    cc%factor = aa%factor*bb%factor
    cc%abbrev = trim(aa%abbrev)//'*'//trim(bb%abbrev)
    cc%name = trim(aa%name)//' * '//trim(bb%name)
 
  end function units_multiply
 
  !-----------------------------------------------
 
  type(unit_t) pure function units_divide(aa, bb) result(cc)
    type(unit_t), intent(in) :: aa
    type(unit_t), intent(in) :: bb
 
    cc%factor = aa%factor/bb%factor
    cc%abbrev = trim(aa%abbrev)//'/'//trim(bb%abbrev)
    cc%name = trim(aa%name)//' / '//trim(bb%name)
 
  end function units_divide
  !-----------------------------------------------
 
  type(unit_t) pure function units_pow(aa, nn) result(cc)
    type(unit_t), intent(in) :: aa
    integer,      intent(in) :: nn
 
    cc%factor = aa%factor**nn
    cc%name = trim(aa%name)
 
    ! We have to do the conversion by hand. This is ugly, but we
    ! cannot use write here since this function might be called inside
    ! another write (stupid Fortran).
 
    select case (nn)
    case (-3)
      cc%abbrev = trim(aa%abbrev)//'^-3'
    case (-2)
      cc%abbrev = trim(aa%abbrev)//'^-2'
    case (-1)
      cc%abbrev = trim(aa%abbrev)//'^-1'
    case (0)
      cc%abbrev = '1'
    case (1)
      cc%abbrev = trim(aa%abbrev)
    case (2)
      cc%abbrev = trim(aa%abbrev)//'^2'
    case (3)
      cc%abbrev = trim(aa%abbrev)//'^3'
    case (4)
      cc%abbrev = trim(aa%abbrev)//'^4'
    case (5)
      cc%abbrev = trim(aa%abbrev)//'^5'
    case default
      cc%abbrev = trim(aa%abbrev)//'^n'
    end select
 
  end function units_pow
 
 
  !-----------------------------------------------
 
  type(unit_t) pure function units_sqrt(aa) result(cc)
    type(unit_t), intent(in) :: aa
 
    cc%factor = sqrt(aa%factor)
    cc%abbrev = 'sqrt('//trim(aa%abbrev)//')'
    cc%name = 'sqrt('//trim(aa%name)//')'
 
  end function units_sqrt
 
end module unit_oct_m
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: