Reference FMUs

A set of hand-coded FMUs for development, testing and debugging of the Functional Mock-up Interface.

BouncingBall - a bouncing ball model with state events
Dahlquist - Dahlquist test equation
Feedthrough - all variable types
Resource - load data from a file
Stair - a counter with time events
StateSpace - arrays and structural parameters
VanDerPol - Van der Pol test equation

Use the fmusim executable to simulate an FMU:

> fmusim --help
Usage: fmusim [OPTION]... [FMU]
Simulate a Functional Mock-up Unit and write the output to result.csv.
  --help                           display this help and exit
  --interface-type [me|cs]         the interface type to use
  --tolerance [TOLERANCE]          relative tolerance
  --start-time [VALUE]             start time
  --stop-time [VALUE]              stop time
  --output-interval [VALUE]        set the output interval
  --start-value [name] [value]     set a start value
  --output-variable [name]         record a specific variable
  --input-file [FILE]              read input from a CSV file
  --output-file [FILE]             write output to a CSV file
  --log-fmi-calls                  log FMI calls
  --fmi-log-file [FILE]            set the FMI log file
  --solver [euler|cvode]           the solver to use
  --early-return-allowed           allow early return
  --event-mode-used                use event mode
  --record-intermediate-values     record outputs in intermediate update
  --initial-fmu-state-file [FILE]  file to read the serialized FMU state
  --final-fmu-state-file [FILE]    file to save the serialized FMU state
Example:
  fmusim BouncingBall.fmu  simulate with the default settings

You can download the pre-built Reference FMUs and fmusim executables from releases.

CSV file structure

fmusim uses CSV (comma separated values) files with the following structure as input and output format.

The file must be UTF-8 encoded.
The first line contains the names of the columns.
Each column name must match a variable name of the respective FMU.
Names that contain commas (,) must be surrounded by double quotes (").
The first column is the independent variable.
The values of the first column must be monotonically increasing.
Every line is terminated by a newline character (\n).
Every column is separated by a comma (,).
Every line must have the same number of columns.
The values must be stored in the same format as the start values of the respective variables in the modelDescription.xml.
String and Binary variables can only be scalars or arrays with only one element.
String values must be surrounded by double quotes (").

Example:

<ModelVariables>
    <Float64 name="time" causality="independent"></Float64>
    <Float64 name="Float64 array">
        <Dimension valueReference="2"></Dimension>
    </Float64>
    <Boolean name="Boolean array">
        <Dimension valueReference="4"></Dimension>
    </Boolean>
    <Binary name="Binary scalar"></Binary>
</ModelVariables>

time,"Float64 array","Boolean array","Binary scalar"
0,1e-2 -1,0 false 1 true,666f6f
0.1,0.02 -2,1 false 0 true,aa6f6f
0.5,0.03 -3,1 true 0 false,66bb6f

Repository structure

<model>

config.h - model specific types and definitions
FMI{1CS|1ME|2|3}.xml - model descriptions
model.c - implementation of the model

include

fmi{|2|3}Functions.h - FMI header files
model.h - generic model interface
cosimulation.h - generic co-simulation interface

src

fmi{1|2|3}Functions.c - FMI implementations
cosimulation.c - generic co-simulation

examples

*.c - various FMI 3.0 import examples
Examples.cmake - CMake configuration for the example projects

fmusim

sources of the fmusim executable

Build the FMUs

To build the FMUs you need CMake and a supported build tool e.g. Visual Studio ≥ 2013 , Xcode or make:

download or clone the repository
open the CMakeGUI
click Browse Source... and select the cloned or downloaded and extracted repository (that contains CMakeLists.txt)
click Browse Build... and select the folder where you want build the FMUs
click Configure and select the generator for your IDE / build tool
select the FMI_VERSION you want to build and optionally the FMI_TYPE (only for FMI 1.0)
click Generate to generate the project files
click Open Project or open the project in your build tool
build the project

The FMUs will be in the dist folder inside the selected build folder.

Building fmusim

To build the fmusim executable, run the build/build_*.py <platform> Python scripts (where <platform> is the platform to build for, e.g. x86_64-windows) and enable WITH_FMUSIM before generating the CMake project.

License and attribution

The Reference FMUs are a fork of the Test FMUs by Dassault Systèmes, which are a fork of the FMU SDK by QTronic, both released under the 2-Clause BSD License.