Description

We want to drop the dreadful muPhi-like boundary condition datafile and switch to an input through YAML data files (as mentioned in #29 (closed)). This is in line with the changes for the parameterization data input (see #86 (closed)).

The new boundary condition input should be match the boundary segmentation input by using the segmentation indices for identification.

Proposal

YAML boundary condition file

Have a new boundary condition data input file in YAML format. The proposal looks like this:

north: # arbitrary name
  index: 1 # association index
  conditions:
    rain_1:
      type: neumann
      value: -5.55e-6
      time: 2000 # single value: extrapolate until finish

    evaporation_1:
      type: dirichlet
      value: [-6, -0] # sequence: linear interpolation of values
      time: [1000, 2000] # sequence: time interval

south:
  index: 2
  conditions:
    water_table:
      type: dirichlet
      value: 0.0
      time: 0

# unspecified boundaries: no-flow
default:
  type: neumann
  value: 0.0

Loadup algorithm

The algorithm has to perform the following steps:

• Create a map: Association index -> BC list
  • Open the YAML file
  • store the default BC
  • iterate over all other segments
  • read the index
  • iterate over conditions, following this algorithm:

• fill in "blanks":

  • compare sets of BC association indices from YAML files and mappings
  • fill missing time intervals with default BC
  • create default BC for missing association indices

• create map: Boundary index -> shared pointer to BC list

  • iterate over all grid boundary faces
  • read boundary index
  • use boundary index map to infer association index and hence BC list

Local operator interface

Adapt FlowBoundary:

FlowBoundary
{
private:
  using BCList = std::list<std::shared_ptr<BoundaryCondition>>;
  using BoundaryConditionStorage = std::vector<BCList>;

  // store a list of boundary conditions for every boundary segment (index)
  BoundaryConditionStorage _bc_storage;
  // store pointers to the currently applied boundary conditions (updated by set_time)
  BCList _bc_time_cache;

public:
  /// Update the time cache
  void set_time (const RF time);

  /// Retrieve the boundary condition
  std::shared_ptr<BoundaryCondition> bc (const Intersection& is);
  
}

How to test the implementation?

New unit test: Create exemplary BC data file and mapping and check internal results (also with variable time)

Related issues

Meta-issue #119 (closed)