mirror of
https://github.com/JuliaFEM/JuliaFEM.jl.git
synced 2026-09-20 01:59:59 +00:00
Jukka Aho
c4afa8347d
New 95-line file for mixed/coupled DOF systems:
- MixedDOF{DOFs}: composition of multiple entity-based DOF types
- Helper functions: is_mixed(), get_dof_types(), num_fields(), get_field_dof_type()
- Support for Stokes (velocity+pressure), 3-field formulations, Taylor-Hood
- DOF ordering: concatenated in field order
- Display formatting for mixed DOF types
Enables mixed interpolation methods with different DOF types per field.
96 lines
2.5 KiB
Julia
96 lines
2.5 KiB
Julia
# This file is a part of JuliaFEM.
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# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE
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"""
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Mixed DOF Types - Entity-Based
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Implementation of mixed/coupled DOF systems where multiple DOF types
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coexist on the same element.
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# Core Type
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- `MixedDOF{DOFs}`: Composition of multiple entity-based DOF types
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# Use Cases
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**Stokes (velocity + pressure):**
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```julia
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MixedDOF{(
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DOF{Vec{2}, Vertex{Triangle{3}}}, # Velocity at vertices
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DOF{Float64, Vertex{Triangle{3}}} # Pressure at vertices
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)}
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```
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**3-Field Formulation (u + p + J):**
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```julia
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MixedDOF{(
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DOF{Vec{3}, Vertex{Tetrahedron{4}}}, # Displacement at vertices
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DOF{Float64, Vertex{Tetrahedron{4}}}, # Pressure at vertices
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DOF{Float64, Edge{Tetrahedron{4}}} # Volumetric DOF on edges
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)}
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```
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**Mixed Interpolation (Taylor-Hood):**
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```julia
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MixedDOF{(
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DOF{Vec{2}, Vertex{Triangle{6}}}, # Quadratic velocity
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DOF{Float64, Vertex{Triangle{3}}} # Linear pressure (different topology!)
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)}
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```
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# DOF Ordering
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Mixed DOFs are concatenated in order:
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```julia
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MixedDOF{(DOF{Vec{2}, Vertex{Triangle{3}}}, DOF{Float64, Vertex{Triangle{3}}})}
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# For Triangle{3}:
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# Field 1: [u1x, u1y, u2x, u2y, u3x, u3y] (6 DOFs from 2×3 vertices)
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# Field 2: [p1, p2, p3] (3 DOFs from 1×3 vertices)
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# Total: [u1x, u1y, u2x, u2y, u3x, u3y, p1, p2, p3] (9 DOFs)
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```
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"""
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# MixedDOF is already defined in api.jl, this file adds helper functions
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# ============================================================================
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# Helper Functions
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# ============================================================================
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"""
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Check if DOF type is mixed.
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"""
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is_mixed(::Type{<:MixedDOF}) = true
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is_mixed(::Type{<:DOF}) = false
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"""
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Get the tuple of constituent DOF types.
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"""
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function get_dof_types(::Type{MixedDOF{DOFs}}) where {DOFs}
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return DOFs.parameters
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end
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"""
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Get number of fields in mixed system.
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"""
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function num_fields(::Type{MixedDOF{DOFs}}) where {DOFs}
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return length(DOFs.parameters)
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end
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"""
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Get DOF type for specific field (1-indexed).
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"""
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function get_field_dof_type(::Type{MixedDOF{DOFs}}, field_idx::Int) where {DOFs}
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return DOFs.parameters[field_idx]
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end
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# ============================================================================
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# Display
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# ============================================================================
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function Base.show(io::IO, ::Type{MixedDOF{DOFs}}) where {DOFs}
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dof_types = [string(T) for T in DOFs.parameters]
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print(io, "MixedDOF{(", join(dof_types, ", "), ")}")
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end
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