salvus.mesh.layered_meshing.utils.split_layered_model

def split_layered_model(
    layered_model: salvus.mesh.layered_meshing.layered_model.layered_model.LayeredModel,
    predicate: Callable[
        [salvus.mesh.layered_meshing.layered_model.layer.Layer], bool
    ],
) -> Tuple[
    Union[
        salvus.mesh.layered_meshing.layered_model.layered_model.LayeredModel,
        NoneType,
    ],
    Union[
        salvus.mesh.layered_meshing.layered_model.layered_model.LayeredModel,
        NoneType,
    ],
]:
    ...

Split a layered model with a predicate that takes a Layer as input.

The predicate will be applied to the layered model layer-by-layer in top-down order. The first time a predicate returns True for a given layer, the layered model is split at that layer’s top interface. To be clear, splitting the following model:

    LayeredModel([
        interface.Hyperplane.at(1.0),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.66),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.33),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.0),
    ])

with the predicate:

`lambda lay: lay.bot.max_elevation == 0.33`

will result in the return value of:

```
(
    LayeredModel([
        interface.Hyperplane.at(1.0),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.66),
    ]),
    LayeredModel([
        interface.Hyperplane.at(0.66),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.33),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.0),
    ])
)
```

while the predicate:

`lambda lay: lay.top.max_elevation = 0.33`

would instead result in the return value of:

```
(
    LayeredModel([
        interface.Hyperplane.at(1.0),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.66),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.33),
    ]),
    LayeredModel([
        interface.Hyperplane.at(0.33),
        material.acoustic.Velocity.from_params(rho=1.0, vp=1.0),
        interface.Hyperplane.at(0.0),
    ])
)
```

It may be that the predicate returns True for the top layer, or that it returns False for all layers. In the first case, the return value of this function will be:

`(None, layered_model)`

signifying that all layers are located below the split. Likewise, if the predicate returns False for all layers, the return value of this function will be:

`(layered_model, None)`

signifying that all layers are located above the split.

Finally: the caller is responsible for ensuring that their layered model is complete, i.e. that is has bounding interfaces. If this is not the case, an exception will be thrown.