Apart from having the library itself loaded, you need to have OpenGeoSys 6 installed to be able to use `r2ogs6`.
## Creating your simulation object
...
To represent a simulation object, `r2ogs6` uses an R6 class called 'OGS6'. (...).
Don't let ... intimidate you, though. Working with your simulation object is easier than it sounds, so let's get to it.
Before we can work with an object, we need to create it. To create it, we need to call the class constructor and provide it with some parameters:
* `sim_name` The name of your simulation
* `sim_id` A simulation ID (defaults to 1, this is used for chaining simulations)
* `sim_path` All relevant files for your simulation will be in here
* `ogs_bin_path` This is the path to the `bin` folder of your OpenGeoSys 6 distribution
* `test_mode` (This defaults to `FALSE` and should be left alone. I'm setting it to `TRUE` for this vignette because it turns off path validation and we haven't supplied a valid `ogs_bin_path`)
Usually, you will only ever define `sim_name`, `sim_path` and `ogs_bin_path`.
## Loading an OpenGeoSys 6 simulation from a project file
The quickest and easiest way to load a simulation is by using an already existing benchmark. If you take a look at the [OpenGeoSys documentation](https://www.opengeosys.org/docs/benchmarks/elliptic/elliptic-dirichlet/), you'll find plenty of benchmarks to choose from along with a link to their project file on GitLab at the top of the respective page.
For demonstration purposes, I will use a project from the `HydroMechanics` benchmarks, which can be found [here](https://gitlab.opengeosys.org/ogs/ogs/-/tree/master/Tests/Data/HydroMechanics/IdealGas/flow_free_expansion).
NOTE: `r2ogs6` has not been tested with every existing benchmark. Due to the large number of input parameters, you might encounter cases where the import fails.
## Setting up your own OpenGeoSys 6 simulation
(...)
### Check the status of your OGS6 simulation object
Since there's plenty of required and optional input parameters, you might get lost while setting up your simulation. To get a brief overview of your simulation, you can use the `OGS6` function `get_status()`. This tells you which input parameters are missing before you can run a simulation.
```{r}
# Call on the OGS6 object (note the R6 style)
ogs6_obj$get_status()
```
Since we haven't defined anything so far, you'll see a lot of red there.
### Knowing what kind of data to add to your OGS6 simulation object
The results of `get_status()` already gave us a hint what we can add. We'll go from there and try to find out more about the possible input data. Say we want to find out more about `process` objects.
```r
# To take a look at the documentation, use ? followed by the name of a class
?r2ogs6_process
```
As a rule of thumb, classes are named with the prefix `r2ogs6_` followed by their XML tag name in the `.prj` file. The only exceptions to this rule are subclasses where this would lead to duplicate class names. The class `r2ogs6_time_loop` for example contains a subclass representing a `process` child element which is not to be confused with the `process` children of the first level `processes` node directly under the root node of the `.prj` file. Because of this, that subclass is named `r2ogs6_tl_process`.
