repot_examples

This repository provides practical usage examples of an abstract data type designed for the repository pattern defined as repot. In this example, the abstract data type base_repository_atype is extended for reading an integer value and real value from repositories in 4 different formats:

• json
• namelist
• user-defined
• in-memory

In-memory here means that the data is not placed in an external file and is held in memory as components of an extended user-defined type.

This repository also provides examples of internal representations relating IDs (keys) to value. One is to use a select-case statement, and another is to use a hashmap.

From the main routine in app/app.f90, we can see that being able to get data through the common interface regardless of the repository types, i.e., external file format or internal representation.

use :: repot
implicit none

class(base_repository_atype), allocatable :: config_repo

call configure_repository(config_repo)

block
    use :: config_ids
    integer(int32) :: num
    real(real64) :: val

    if (config_repo%find(Config_ID_Number_of_Iterations)) &
        call config_repo%get(Config_ID_Number_of_Iterations, num)

    if (config_repo%find(Config_ID_Initial_Value)) &
        call config_repo%get(Config_ID_Initial_Value, val)

    print '(A,":", g0)', Config_ID_Initial_Value, val
    print '(A,":", g0)', Config_ID_Number_of_Iterations, num
end block

The examples require the following to build:

• Modern Fortran compiler
  • gfortran 11.2 bundled with quickstart Fortran on Windows
  • Intel Fortran Classic 2021.5.0 Build 20211109_000000
  • NAG Fortran 7.1 Build 7117
• Fortran Package Manager (fpm) 0.7.0 alpha
• JSON-Fortran
• stdlib
• M_CLI2

Get the code

To get the code, execute the following command:

git clone https://github.com/degawa/repot_examples.git
cd repot_examples

gfortran

build

To build the example using fpm with gfortran, execute the following command:

fpm build

execute

Execute the example with command line arguments. The example reads values from the data storage specified by the arguments.

>fpm run -- --format "in_memory"
initial value:4.000000000000000
number of iterations:100

>fpm run -- --format "in_memory_hashmap"
initial value:9.0000000000000000
number of iterations:25

>cat app/config.json
{
    "unknown": {
        "initial value": 1.0
    },
    "iterative solver": {
        "number of iterations": 1
    }
}
>fpm run -- --format "json" --filename "app/config.json"
initial value:1.0000000000000000
number of iterations:1

>cat app/config.nml
&simulation_configulation
    config%initial_value = -100d0
    config%number_of_iterations = 20
/

>fpm run -- --format "namelist" --filename "app/config.nml"
initial value:-100.00000000000000
number of iterations:20

>cat app/config
-1.0
1000
>fpm run -- --format "user_defined" --filename "app/config"
initial value:-1.0000000000000000
number of iterations:1000

Intel Fortran

build

To build the example using fpm with gfortran, execute the following command:

fpm build --compiler ifort

execute

Execute the example with command line arguments. The example reads values from the data storage specified by the arguments.

>fpm run --compiler ifort -- --format "in_memory"
initial value:4.000000000000000
number of iterations:100

>fpm run --compiler ifort -- --format "in_memory_hashmap"
initial value:9.0000000000000000
number of iterations:25

>fpm run --compiler ifort -- --format "json" --filename "app/config.json"
initial value:1.0000000000000000
number of iterations:1

>fpm run --compiler ifort -- --format "namelist" --filename "app/config.nml"
initial value:-100.00000000000000
number of iterations:20

>fpm run --compiler ifort -- --format "user_defined" --filename "app/config"
initial value:-1.0000000000000000
number of iterations:1000

NAG Fortran

modification of JSON-Fortran

NAG Fortran compiler cannot build json-fortran because the preprocessor's behavior differs from gfortran and Intel Fortran. Some modifications are required to build json-fortran.

• Copy the json_initialize_dummy_arguments.inc to json_initialize_dummy_arguments_nagfor.inc and add one more & to the final line of json_initialize_dummy_arguments_nagfor.inc.

-strict_integer_type_checking &
+strict_integer_type_checking &&

• Define the preprocessor macro in the #if block added to the top of json_value_module.F90 and json_file_module.F90 for choosing the appropriate inc file.

+#if defined(NAGFOR)
+#define JSON_INIT_DUMMY_ARGS "json_initialize_dummy_arguments_nagfor.inc"
+#else
+#define JSON_INIT_DUMMY_ARGS "json_initialize_dummy_arguments.inc"
+#endif

• Replace the #include target to the macro in json_value_module.F90 and json_file_module.F90.

-#include "json_initialize_dummy_arguments.inc"
+#include JSON_INIT_DUMMY_ARGS

build

To build the example using fpm with gfortran, execute the following command:

fpm build --compiler nagfor --flag "-I build\dependencies\json-fortran\src"

execute

Execute the example with command line arguments. The example reads values from the data storage specified by the arguments.

>fpm run --compiler nagfor --flag "-I build\dependencies\json-fortran\src" -- --format "in_memory"
initial value:4.000000000000000
number of iterations:100

>fpm run --compiler nagfor --flag "-I build\dependencies\json-fortran\src" -- --format "in_memory_hashmap"
initial value:9.000000000000000
number of iterations:25

>fpm run --compiler nagfor --flag "-I build\dependencies\json-fortran\src" -- --format "json" --filename "app/config.json"
initial value:1.000000000000000
number of iterations:1

>fpm run --compiler nagfor --flag "-I build\dependencies\json-fortran\src" -- --format "namelist" --filename "app/config.nml"
initial value:-100.0000000000000
number of iterations:20

>fpm run --compiler nagfor --flag "-I build\dependencies\json-fortran\src" -- --format "user_defined" --filename "app/config"
initial value:-1.000000000000000
number of iterations:1000