An example of implementing the Fortran bindings for the CSDMS Basic Model Interface (BMI).

This is an example of implementing a BMI for a simple model that solves the diffusion equation on a uniform rectangular plate with Dirichlet boundary conditions. Tests and examples of using the BMI are provided. The model is written in Fortran 90. The BMI is written in Fortran 2003.

This repository is organized with the following directories:

heat

Holds the model and a sample main program

bmi_heat

Holds the BMI for the model and a main program to run the model through its BMI

test

Unit tests for the BMI-ed model

example

Examples of controlling the model through its BMI

This example can be built on Linux, macOS, and Windows.

Prerequisites:

• A Fortran compiler
• CMake or Fortran Package Manager
• If using CMake, the Fortran BMI bindings. Follow the build and install directions given in the README in that repository. You can choose to build them from source or install them through a conda binary. If using fpm, the binding will be automatically downloaded and built for you.
• pkg-config

To build this example from source with CMake, using the current Fortran BMI version, run

mkdir _build && cd _build
cmake .. -DCMAKE_INSTALL_PREFIX=<path-to-installation>
make

where <path-to-installation> is the base directory in which the Fortran BMI bindings have been installed (/usr/local is the default). When installing into a conda environment, use the $CONDA_PREFIX environment variable.

Then, to install (on both Linux and macOS):

make install

The installation will look like (on macOS, using v2.0 of the Fortran BMI specification):

.
|-- bin
|   |-- run_bmiheatf
|   `-- run_heatf
|-- include
|   |-- bmif_2_0.mod
|   |-- bmiheatf.mod
|   `-- heatf.mod
`-- lib
    |-- libbmif.a
    |-- libbmif.2.0.2.dylib
    |-- libbmif.dylib -> libbmif.2.0.2.dylib
    |-- libbmiheatf.dylib
    |-- libheatf.dylib
    `-- pkgconfig
        |-- bmif.pc
        |-- bmiheatf.pc
        `-- heatf.pc

From the build directory, run unit tests and examples of using the sample implementation with

ctest

An additional prerequisite is needed for Windows:

• Microsoft Visual Studio 2017 or Microsoft Build Tools for Visual Studio 2017

To configure this example from source with cmake using the current Fortran BMI version, run the following in a Developer Command Prompt

mkdir _build && cd _build
cmake .. ^
  -G "NMake Makefiles" ^
  -DCMAKE_INSTALL_PREFIX=<path-to-installation> ^
  -DCMAKE_BUILD_TYPE=Release

where <path-to-installation> is the base directory in which the Fortran BMI bindings have been installed. The default is "C:\Program Files (x86)". Note that quotes and an absolute path are needed. When using a conda environment, use "%CONDA_PREFIX%\Library".

Then, to build and install:

cmake --build . --target install --config Release

From the build directory, run unit tests and examples of using the sample implementation with

ctest

If you don't already have fpm installed, you can do so via Conda:

conda install fpm -c conda-forge

Then, to build and install:

fpm build --profile release
fpm install --prefix <path-to-installation>

where <path-to-installation> is the base directory in which to install the model. Installation is optional.

To run the tests:

fpm test -- test/sample.cfg

Here, test/sample.cfg is passed as a command line parameter to the run executables, and tells the tests where to find the test config file.

To run all of the examples:

fpm run --example --all -- example

Similarly, example tells the example executables to look in the example directory for config files. To run individual tests:

fpm run --example <example-name> -- example

Where <example-name> is the name of the example to run. To see a list of available examples, run fpm run --example. Note that the non-BMI heat model executable is not built by default when using fpm. If you want to build and install this too, you can do so from the heat directory:

cd heat
fpm build --profile release
fpm install --prefix <path-to-installation>

Run the heat model through its BMI with the run_bmiheatf program, which takes a model configuration file (see the example directory for a sample) as a required parameter. If run_bmiheatf is in your path, run it with

run_bmiheatf test1.cfg

Output from the model is written to the file bmiheatf.out in the current directory.

If you built the model using fpm, you can alternatively run the program using

fpm run -- test.cfg