Style Guide for SHEMAT-Suite v8.00

Case

Keywords

All standard fortran keywords (including all data types and intrinsic functions) are written in lowercase.

Keywords

subroutine, include, implicit none, module, end module,
allocatable, deallocate, stop, external, call, go to

Data types

double precision, integer, character, logical

Intrinsic functions

max, min, sin

Functions, clauses, loops

• write(...), no empty space between write and the first parenthesis
• read(...), no empty space between read and the first parenthesis
• open(...), no empty space between open and the first parenthesis
• close(...), no empty space between close and the first parenthesis
• allocate(...), no empty space between allocate and the first parenthesis
• deallocate(...), no empty space between deallocate and the first parenthesis
• One empty space between if and the first parenthesis, three empty spaces below if

if (..) then
   a=b
end if	

• Three empty spaces below do

do i = 1, n
  a(i)=b(i)
end do

Subroutines and Functions

Possibly capitalize first letter to distinguish from arrays.

subroutine My_sub ()

function My_func ()

Declaration of variables

Best practice: Do not use kind=4 specification, because it is compiler-dependent.

integer, dimension (3), intent (in) :: i
integer :: ismpl
double precision, parameter :: x = 3.0d0
double precision, intent (out) :: y
double precision :: z
logical :: statement
character (len=20) :: line

Use :: and one space before and after.

Try to use intent (in) and intent (out). Use one white-space after intent and before the parenthesis. Exception: Do not user intent (in) or intent (out) for the variable ismpl. This leads to OpenMP-errors.

In subroutines, first define dummy (input/output) variables, then local variables.

Loops

Try to avoid exit or cycle.

Arrays

Use brackets, when operating on whole arrays

array(:) = array1(:) + array2(:)

Modules

Possibly use protected (readable, but not writable outside the module)

Comments

Use !.

Do not use c, C, or *.

! is also included in Include-Files.

Two indentations are accepted for comment lines:

• Comment lines starting at Character 1 with !

!     if "restart" option is used
      logical test_option
      external test_option

• Comment lines starting with ! at the indentation of the following line of Fortran code.

           ! Length of the state vector
           lstate0 = i0*j0*k0 

Line break

Use &.

Do not use +.

& is included at the end of the line that is continued.

Strings

Since Fortran 2003, allocatable strings exist, possibly these could be used in SHEMAT-Suite.

Code lines

Normal code should only start in the 1st column (free format, fixed format is not necessarily needed).

Try to keep the lines below 80 characters.

Comparison operators

• Use ==, instead of .eq
• Use <, instead of .lt
• Use <=, instead of .le
• Use >, instead of .gt
• Use >=, instead of .ge
• Use \=, instead of .ne

Doxygen headers

Example doxygen header:

!>    @brief main program for forward simulation (only)
!>    @details
!>
!> **SHEMAT-Suite (Simulator for HEat and MAss Transport)** is a
!> numerical code for computing flow, heat and species transport
!> equations in porous media. The governing equations of the code are
!> the groundwater flow equation, the heat transport equation and the
!> species transport equation. \n\n
!>
!> SHEMAT-Suite includes parameter estimation and data assimilation
!> approaches, both stochastic (Monte Carlo, ensemble Kalman filter)
!> and deterministic (Bayesian inversion using automatic
!> differentiation for calculating derivatives).\n\n
!>
!> Note: To be able to use input file parsing with hdf5, the
!> hdf5-input-files have to be generated using the script:
!> `convert_to_hdf5.py`. This script can be found in the repository
!> `SHEMAT-Suite_Scripts` under
!> `python/preprocessing/convert_to_hdf5.py`.

The header should always contain the following fields

• @brief: Brief description
• @details: Detailed description and notes, sources. Should recall the brief description, so that the html from doxygen is nicely readable.