Particle packing #529
Particle packing #529
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| - `is_boundary`: When `is_boundary=true`, boundary particles will be sampled | ||
| and packed in an offset surface of the `boundary`. | ||
| The thickness of the boundary is specified by passing the | ||
| [`SignedDistanceField`](@ref) of `boundary` with: | ||
| - `use_for_boundary_packing=true` | ||
| - `max_signed_distance=boundary_thickness` |
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I don't understand this description. What is this option doing?
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If set to true the ParticlePackingSystem packs only boundary particles of the geometry.
If set to false (default) the ParticlePackingSystem packs the particles inside the geometry.
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So there is always only one system packed? Either inside or boundary? This is not clear to me from the docs.
And I still don't understand this description.
| - `is_boundary`: When `is_boundary=true`, boundary particles will be sampled | |
| and packed in an offset surface of the `boundary`. | |
| The thickness of the boundary is specified by passing the | |
| [`SignedDistanceField`](@ref) of `boundary` with: | |
| - `use_for_boundary_packing=true` | |
| - `max_signed_distance=boundary_thickness` | |
| - `pack_boundary`: When `pack_boundary=false`, the particles in `boundary` | |
| are fixed and the particles in `shape` are packed. | |
| When `pack_boundary=true`, the particles in `shape` are fixed | |
| and the particles in `boundary` are fixed. | |
| It often makes sense to first pack the `shape` against the `boundary` | |
| and then in the next step `boundary` against the packed `shape`. | |
| The thickness of the boundary is specified by passing the | |
| [`SignedDistanceField`](@ref) of `boundary` with: | |
| - `use_for_boundary_packing=true` | |
| - `max_signed_distance=boundary_thickness` |
Is this correct? Is it not possible to pack both at the same time?
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No, that's not correct.
I have two different systems. One is filled with the particles inside the geometry (fluid) and one is filled with particles outside the geometry (boundary). These are independent systems that interact with each other.
The only difference between these systems is the shift condition used to constrain particles onto the surface.
For example:
packing_system = ParticlePackingSystem(shape_sampled; boundary=geometry,
signed_distance_field, tlsph=tlsph,
background_pressure)
boundary_system = ParticlePackingSystem(boundary_sampled; boundary=geometry,
is_boundary=true, signed_distance_field,
tlsph=tlsph, background_pressure)
semi = Semidiscretization(packing_system, boundary_system)
| # Initialize neighborhood search with signed distances | ||
| PointNeighbors.initialize_grid!(nhs, stack(signed_distance_field.positions)) |
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@efaulhaber should I use a full grid nhs here? The positions of the signed_distance_field are of course static. Or what is the best choice here?
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Yes, by default the nhs should be using a FullGridCellList. You need to set this in the kwarg.
This cell list is faster and GPU-compatible. Only downsides are 1. one needs to specify a bounding box and 2. the domain is constrained to this bounding box. Here you know the bounding box and particles should never leave it, right?
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Here you know the bounding box and particles should never leave it, right?
Yes, exactly.
based on #439 and #436