Add update_subgrid_level to BMI functions (#986)

Fixes #985

build/libribasim/src/libribasim.jl

@@ -100,6 +100,12 @@ Base.@ccallable function update_until(time::Cdouble)::Cint
     end
 end
 
+Base.@ccallable function update_subgrid_level()::Cint
+    @try_c begin
+        Ribasim.update_subgrid_level(model)
+    end
+end
+
 Base.@ccallable function get_current_time(time::Ptr{Cdouble})::Cint
     @try_c begin
         t = BMI.get_current_time(model)

core/src/bmi.jl

@@ -633,6 +633,11 @@ function BMI.update_until(model::Model, time)::Model
     return model
 end
 
+function update_subgrid_level(model::Model)::Model
+    update_subgrid_level!(model.integrator)
+    return model
+end
+
 function BMI.get_value_ptr(model::Model, name::AbstractString)
     if name == "volume"
         model.integrator.u.storage

python/ribasim_api/tests/test_bmi.py

@@ -57,6 +57,17 @@ def test_update_until(libribasim, basic, tmp_path):
     assert actual_time == pytest.approx(expected_time)
 
 
+def test_update_subgrid_level(libribasim, basic, tmp_path):
+    basic.write(tmp_path / "ribasim.toml")
+    config_file = str(tmp_path / "ribasim.toml")
+    libribasim.initialize(config_file)
+    libribasim.update_subgrid_level()
+    level = libribasim.get_value_ptr("subgrid_level")
+    # The subgrid levels are initialized with NaN.
+    # After calling update, they should have regular values.
+    assert np.isfinite(level).all()
+
+
 def test_get_var_type(libribasim, basic, tmp_path):
     basic.write(tmp_path / "ribasim.toml")
     config_file = str(tmp_path / "ribasim.toml")

python/ribasim_testmodels/ribasim_testmodels/basic.py

@@ -39,7 +39,16 @@ def basic_model() -> ribasim.Model:
     state = pd.DataFrame(
         data={"node_id": static["node_id"], "level": 0.04471158417652035}
     )
-    basin = ribasim.Basin(profile=profile, static=static, state=state)
+    # This is a 1:1 translation.
+    subgrid = pd.DataFrame(
+        data={
+            "node_id": profile["node_id"],
+            "subgrid_id": profile["node_id"],
+            "basin_level": profile["level"],
+            "subgrid_level": profile["level"],
+        }
+    )
+    basin = ribasim.Basin(profile=profile, static=static, state=state, subgrid=subgrid)
 
     # Setup linear resistance:
     linear_resistance = ribasim.LinearResistance(