source: palm/trunk/UTIL/inifor/src/inifor_util.f90 @ 3611

!> @file src/inifor_util.f90
!------------------------------------------------------------------------------!
! This file is part of the PALM model system.
!
! PALM 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.
!
! PALM 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
! PALM. If not, see <http://www.gnu.org/licenses/>.
!
! Copyright 2017-2018 Leibniz Universitaet Hannover
! Copyright 2017-2018 Deutscher Wetterdienst Offenbach
!------------------------------------------------------------------------------!
!
! Current revisions:
! -----------------
! 
! 
! Former revisions:
! -----------------
! $Id: inifor_util.f90 3557 2018-11-22 16:01:22Z banzhafs $
! Updated documentation
! 
! 
! 3447 2018-10-29 15:52:54Z eckhard
! Renamed source files for compatibilty with PALM build system
! 
! 
! 3395 2018-10-22 17:32:49Z eckhard
! New routines for computing potential temperature and moist air density
! Increased number of digits in real-to-str conversion
! 
! 3183 2018-07-27 14:25:55Z suehring
! Improved real-to-string conversion
! 
! 
! 3182 2018-07-27 13:36:03Z suehring
! Initial revision
!
! 
!
! Authors:
! --------
!> @author Eckhard Kadasch (Deutscher Wetterdienst, Offenbach)
!
! Description:
! ------------
!> The util module provides miscellaneous utility routines for INIFOR.
!------------------------------------------------------------------------------!
 MODULE util

    USE, INTRINSIC :: ISO_C_BINDING,                                           &
        ONLY :  C_CHAR, C_INT, C_PTR, C_SIZE_T
    USE defs,                                                                  &
        ONLY :  dp, PI, DATE, SNAME
    USE types,                                                                 &
        ONLY :  grid_definition

    IMPLICIT NONE

!------------------------------------------------------------------------------!
! Description:
! ------------
!> Fortran implementation of C's struct tm for representing points in time
!------------------------------------------------------------------------------!
    TYPE, BIND(c) :: tm_struct
       INTEGER(C_INT) :: tm_sec     !< seconds after the minute [0, 61]
       INTEGER(C_INT) :: tm_min     !< minutes after the hour [0, 59]
       INTEGER(C_INT) :: tm_hour    !< hours since midnight [0, 23]
       INTEGER(C_INT) :: tm_mday    !< day of the month [1, 31]
       INTEGER(C_INT) :: tm_mon     !< month since January [0, 11]
       INTEGER(C_INT) :: tm_year    !< years since 1900
       INTEGER(C_INT) :: tm_wday    !< days since Sunday [0, 6]
       INTEGER(C_INT) :: tm_yday    !< days since January 1st [0, 356]
       INTEGER(C_INT) :: tm_isdst   !< Daylight Saving Time flag
    END TYPE

    INTERFACE

!------------------------------------------------------------------------------!
! Description:
! ------------
!> Interface to C's strptime function, which converts a string to a tm
!> structure.
!------------------------------------------------------------------------------!
       FUNCTION strptime(string, format, timeinfo) BIND(c, NAME='strptime')
          IMPORT :: C_CHAR, C_SIZE_T, tm_struct

          IMPLICIT NONE

          CHARACTER(KIND=C_CHAR), DIMENSION(*), INTENT(IN) ::  string, format
          TYPE(tm_struct), INTENT(OUT)                     ::  timeinfo

          INTEGER(C_SIZE_T)                                ::  strptime
       END FUNCTION


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Interface to C's strftime function, which converts the given 'timeinfo'
!> structure to a string in the given 'format'.
!------------------------------------------------------------------------------!
       FUNCTION strftime(string, string_len, format, timeinfo) BIND(c, NAME='strftime')
          IMPORT :: C_CHAR, C_SIZE_T, tm_struct

          IMPLICIT NONE

          CHARACTER(KIND=C_CHAR), DIMENSION(*), INTENT(OUT) ::  string
          CHARACTER(KIND=C_CHAR), DIMENSION(*), INTENT(IN)  ::  format
          INTEGER(C_SIZE_T), INTENT(IN)                     ::  string_len
          TYPE(tm_struct), INTENT(IN)                       ::  timeinfo

          INTEGER(C_SIZE_T)                                 ::  strftime
       END FUNCTION


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Interface to C's mktime function, which converts the given tm structure to
!> Unix time (number of seconds since 0 UTC, 1st January 1970). INIFOR uses the
!> side effect that a call to mktime noramlizes the given 'timeinfo' structure,
!> e.g. increments the date if hours overfow 24.
!------------------------------------------------------------------------------!
       FUNCTION mktime(timeinfo) BIND(c, NAME='mktime')
          IMPORT :: C_PTR, tm_struct

          IMPLICIT NONE

          TYPE(tm_struct), INTENT(IN) ::  timeinfo

          TYPE(C_PTR)                 ::  mktime
       END FUNCTION

    END INTERFACE

 CONTAINS

!------------------------------------------------------------------------------!
! Description:
! ------------
!> Takes a string of the form YYYYMMDDHH, adds the given number of hours to its
!> tm structure representation, and returns the corresponding string in the same
!> format
!------------------------------------------------------------------------------!
    CHARACTER(LEN=DATE) FUNCTION add_hours_to(date_string, hours)
       CHARACTER(LEN=DATE), INTENT(IN)          ::  date_string
       INTEGER, INTENT(IN)                      ::  hours

       CHARACTER(KIND=C_CHAR, LEN=*), PARAMETER ::  format_string = "%Y%m%d%H"
       CHARACTER(KIND=C_CHAR, LEN=DATE)         ::  c_date_string
       TYPE(C_PTR)                              ::  c_pointer
       TYPE(tm_struct)                          ::  time_info
       INTEGER                                  ::  err

       c_date_string = date_string

       ! Convert C string to C tm struct
       CALL init_tm(time_info)
       err = strptime(c_date_string, format_string, time_info)
    
       ! Manipulate and normalize C tm struct
       time_info % tm_hour = time_info % tm_hour + hours
       c_pointer = mktime(time_info)

       ! Convert back to C string
       err = strftime(c_date_string, INT(DATE, KIND=C_SIZE_T),                 &
                      format_string, time_info)

       add_hours_to = c_date_string
    END FUNCTION


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Print all members of the given tm structure
!------------------------------------------------------------------------------!
    SUBROUTINE print_tm(timeinfo)
       TYPE(tm_struct), INTENT(IN) :: timeinfo

       PRINT *, "sec: ", timeinfo % tm_sec,  &  !< seconds after the minute [0, 61]
                "min: ", timeinfo % tm_min,  &  !< minutes after the hour [0, 59]
                "hr:  ", timeinfo % tm_hour, &  !< hours since midnight [0, 23]
                "day: ", timeinfo % tm_mday, &  !< day of the month [1, 31]
                "mon: ", timeinfo % tm_mon,  &  !< month since January [0, 11]
                "yr:  ", timeinfo % tm_year, &  !< years since 1900
                "wday:", timeinfo % tm_wday, &  !< days since Sunday [0, 6]
                "yday:", timeinfo % tm_yday, &  !< days since January 1st [0, 356]
                "dst: ", timeinfo % tm_isdst    !< Daylight Saving time flag
    END SUBROUTINE print_tm

    
!------------------------------------------------------------------------------!
! Description:
! ------------
!> Initialize the given tm structure with zero values
!------------------------------------------------------------------------------!
    SUBROUTINE init_tm(timeinfo)
       TYPE(tm_struct), INTENT(INOUT) :: timeinfo

       timeinfo % tm_sec   = 0
       timeinfo % tm_min   = 0
       timeinfo % tm_hour  = 0
       timeinfo % tm_mday  = 0
       timeinfo % tm_mon   = 0
       timeinfo % tm_year  = 0
       timeinfo % tm_wday  = 0
       timeinfo % tm_yday  = 0

       ! We use UTC times, so marking Daylight Saving Time (DST) 'not available'
       ! (< 0). If this is set to 0, mktime will convert the timeinfo to DST and
       ! add one hour.
       timeinfo % tm_isdst = -1
    END SUBROUTINE init_tm


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Fill the given array with values equally spaced between and including start
!> and stop
!------------------------------------------------------------------------------!
    SUBROUTINE linspace(start, stop, array)

       REAL(dp), INTENT(IN)    ::  start, stop
       REAL(dp), INTENT(INOUT) ::  array(0:)
       INTEGER                 ::  i, n

       n = UBOUND(array, 1)

       IF (n .EQ. 0)  THEN

          array(0) = start

       ELSE

          DO i = 0, n
             array(i) = start + REAL(i, dp) / n * (stop - start)
          END DO

       END IF
       
    END SUBROUTINE linspace


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Reverse the order of the third (vertical) array dimension from top-down
!> (COSMO) to bottom-up (PALM)
!------------------------------------------------------------------------------!
    SUBROUTINE reverse(input_arr)

       REAL(dp), INTENT(INOUT) ::  input_arr(:,:,:)

       input_arr = input_arr(:,:,size(input_arr, 3):1:-1)

    END SUBROUTINE reverse


!------------------------------------------------------------------------------!
! Description:
! ------------
!> 
!------------------------------------------------------------------------------!
    SUBROUTINE deaverage(avg_1, t1, avg_2, t2, avg_3, t3)

       REAL(dp), DIMENSION(:,:,:), INTENT(IN)  ::  avg_1, avg_2
       REAL(dp), INTENT(IN)                    ::  t1, t2, t3
       REAL(dp), DIMENSION(:,:,:), INTENT(OUT) ::  avg_3

       REAL(dp)                                ::  ti
 
       ti = 1.0_dp / t3

       avg_3(:,:,:) = ti * ( t2 * avg_2(:,:,:) - t1 * avg_1(:,:,:) )

    END SUBROUTINE deaverage


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Compute the COSMO-DE/-D2 basic state pressure profile
!------------------------------------------------------------------------------!
    SUBROUTINE get_basic_state(z, beta, p_sl, t_sl, rd, g, p0)

       REAL(dp), INTENT(IN)  ::  z(1:)  !< height [m]
       REAL(dp), INTENT(IN)  ::  beta   !< logarithmic lapse rate, dT / d ln(p) [K]
       REAL(dp), INTENT(IN)  ::  p_sl   !< reference pressure [Pa]
       REAL(dp), INTENT(IN)  ::  t_sl   !< reference tempereature [K]
       REAL(dp), INTENT(IN)  ::  rd     !< ideal gas constant of dry air [J/kg/K]
       REAL(dp), INTENT(IN)  ::  g      !< acceleration of Earth's gravity [m/s^2]
       REAL(dp), INTENT(OUT) ::  p0(1:) !< COSMO basic state pressure [Pa]
       REAL(dp) ::  root_frac, factor   !< precomputed factors

       factor = - t_sl / beta
       root_frac = (2.0_dp * beta * g) / (rd * t_sl*t_sl)

       p0(:) = p_sl * EXP(                                                     &
                  factor * ( 1.0_dp - SQRT( 1.0_dp - root_frac * z(:) ) )      &
       )

    END SUBROUTINE get_basic_state


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Converts the absolute temperature to the potential temperature in place using
!> the identity a^b = e^(b ln(a)).
!>
!>     theta = T * (p_ref/p)^(R/c_p) = T * e^( R/c_p * ln(p_ref/p) )
!------------------------------------------------------------------------------!
    SUBROUTINE potential_temperature(t, p, p_ref, r, cp)
       REAL(dp), DIMENSION(:,:,:), INTENT(INOUT) ::  t
       REAL(dp), DIMENSION(:,:,:), INTENT(IN)    ::  p
       REAL(dp), INTENT(IN)                      ::  p_ref, r, cp
       REAL(dp)                                  ::  rcp

       rcp = r/cp
       t(:,:,:) =  t(:,:,:) * EXP( rcp * LOG(p_ref / p(:,:,:)) )

    END SUBROUTINE potential_temperature


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Compute the density in place of the given temperature (t_rho).
!------------------------------------------------------------------------------!
   SUBROUTINE moist_density(t_rho, p, qv, rd, rv)
       REAL(dp), DIMENSION(:,:,:), INTENT(INOUT) ::  t_rho
       REAL(dp), DIMENSION(:,:,:), INTENT(IN)    ::  p, qv
       REAL(dp), INTENT(IN)                      ::  rd, rv

       t_rho(:,:,:) = p(:,:,:) / (                                             &
          (rv * qv(:,:,:) + rd * (1.0_dp - qv(:,:,:))) * t_rho(:,:,:)          &
       )

    END SUBROUTINE moist_density


    ! Convert a real number to a string in scientific notation
    ! showing four significant digits.
    CHARACTER(LEN=SNAME) FUNCTION real_to_str(val, format)

        REAL(dp), INTENT(IN)                   ::  val
        CHARACTER(LEN=*), OPTIONAL, INTENT(IN) ::  format

        IF (PRESENT(format))  THEN
           WRITE(real_to_str, format) val
        ELSE
           WRITE(real_to_str, '(E11.4)') val
        END IF
        real_to_str = ADJUSTL(real_to_str)

    END FUNCTION real_to_str


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Converts the given real value to a string
!------------------------------------------------------------------------------!
    CHARACTER(LEN=16) FUNCTION real_to_str_f(val)

        REAL(dp), INTENT(IN) ::  val

        WRITE(real_to_str_f, '(F16.8)') val
        real_to_str_f = ADJUSTL(real_to_str_f)

    END FUNCTION real_to_str_f


!------------------------------------------------------------------------------!
! Description:
! ------------
!> Converts the given integer value to a string
!------------------------------------------------------------------------------!
    CHARACTER(LEN=10) FUNCTION str(val)

        INTEGER, INTENT(IN) ::  val

        WRITE(str, '(i10)') val
        str = ADJUSTL(str)

    END FUNCTION str


!------------------------------------------------------------------------------!
! Description:
! ------------
!> If the given path is not conlcuded by a slash, add one.
!------------------------------------------------------------------------------!
    SUBROUTINE normalize_path(path)
        
        CHARACTER(LEN=*), INTENT(INOUT) ::  path
        INTEGER ::  n

        n = LEN_TRIM(path)

        IF (path(n:n) .NE. '/')  THEN
           path = TRIM(path) // '/'
        END IF

    END SUBROUTINE

 END MODULE