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Remove AccelerationMax buffer and compute max acceleration from Acceleration vector #161

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Remove AccelerationMax buffer and compute max acceleration from Acceleration vector #161

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de0abae
Avoid AccelerationMax buffer
AhmedSalih3d Jan 21, 2026
af325aa
Thread max acceleration reduction
AhmedSalih3d Jan 21, 2026
e81f923
Avoid threadid in max reduction
AhmedSalih3d Jan 21, 2026
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23 changes: 9 additions & 14 deletions src/SPHCellList.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ using LinearAlgebra
SimConstants, SimParticles, ParticleRanges,
CellDict, NeighborCellLists, dρdtI,
Acceleration, ∇Cᵢ,
∇◌rᵢ, AccelerationMax;
∇◌rᵢ;
Position = SimParticles.Position,
Density = SimParticles.Density,
Pressure = SimParticles.Pressure,
Expand Down Expand Up @@ -84,7 +84,6 @@ using LinearAlgebra

dρdtI[i] = dρdt_acc
Acceleration[i] = acc_acc
AccelerationMax[i] = norm(acc_acc)
end

return nothing
Expand All @@ -95,7 +94,7 @@ using LinearAlgebra
SimConstants, SimParticles, ParticleRanges,
CellDict, NeighborCellLists, dρdtI,
Acceleration, ∇Cᵢ,
∇◌rᵢ, AccelerationMax;
∇◌rᵢ;
Position = SimParticles.Position,
Density = SimParticles.Density,
Pressure = SimParticles.Pressure,
Expand Down Expand Up @@ -153,7 +152,6 @@ using LinearAlgebra
Acceleration[i] = acc_acc
Kernel[i] = kernel_acc
KernelGradient[i] = kernel_grad_acc
AccelerationMax[i] = norm(acc_acc)
end

return nothing
Expand All @@ -164,7 +162,7 @@ using LinearAlgebra
SimConstants, SimParticles, ParticleRanges,
CellDict, NeighborCellLists, dρdtI,
Acceleration, ∇Cᵢ,
∇◌rᵢ, AccelerationMax;
∇◌rᵢ;
Position = SimParticles.Position,
Density = SimParticles.Density,
Pressure = SimParticles.Pressure,
Expand Down Expand Up @@ -221,7 +219,6 @@ using LinearAlgebra
Acceleration[i] = acc_acc
∇Cᵢ[i] = shift_c_acc
∇◌rᵢ[i] = shift_r_acc
AccelerationMax[i] = norm(acc_acc)
end

return nothing
Expand All @@ -232,7 +229,7 @@ using LinearAlgebra
SimConstants, SimParticles, ParticleRanges,
CellDict, NeighborCellLists, dρdtI,
Acceleration, ∇Cᵢ,
∇◌rᵢ, AccelerationMax;
∇◌rᵢ;
Position = SimParticles.Position,
Density = SimParticles.Density,
Pressure = SimParticles.Pressure,
Expand Down Expand Up @@ -295,7 +292,6 @@ using LinearAlgebra
KernelGradient[i] = kernel_grad_acc
∇Cᵢ[i] = shift_c_acc
∇◌rᵢ[i] = shift_r_acc
AccelerationMax[i] = norm(acc_acc)
end

return nothing
Expand Down Expand Up @@ -721,7 +717,6 @@ using LinearAlgebra
TimeSteppingMode = SimMetaData.TimeSteppingMode

@no_escape begin
AccelerationMax = @alloc(FloatType, length(Position))
dt₂ = dt * 0.5

SimMetaData.IndexCounter = UpdateNeighbors!(SimParticles, SimKernel.H⁻¹, SortingScratchSpace, ParticleRanges, UniqueCells, CellDict)
Expand All @@ -737,7 +732,7 @@ using LinearAlgebra
@timeit SimMetaData.HourGlass "00b Init NeighborLoop" NeighborLoopPerParticle!(
SimDensityDiffusion, SimViscosity, SimKernel, SimMetaData,
SimConstants, SimParticles, ParticleRanges, CellDict,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ, AccelerationMax,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ,
)
end

Expand Down Expand Up @@ -775,7 +770,7 @@ using LinearAlgebra
@timeit SimMetaData.HourGlass "04 First NeighborLoop" NeighborLoopPerParticle!(
SimDensityDiffusion, SimViscosity, SimKernel, SimMetaData,
SimConstants, SimParticles, ParticleRanges, CellDict,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ, AccelerationMax,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ,
)

@timeit SimMetaData.HourGlass "05 Update To Half TimeStep" HalfTimeStep(SimMetaData, SimConstants, SimParticles, Positionₙ⁺, Velocityₙ⁺, ρₙ⁺, dρdtI, dt₂)
Expand All @@ -788,7 +783,7 @@ using LinearAlgebra
@timeit SimMetaData.HourGlass "08 Second NeighborLoop" NeighborLoopPerParticle!(
SimDensityDiffusion, SimViscosity, SimKernel, SimMetaData,
SimConstants, SimParticles, ParticleRanges, CellDict,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ, AccelerationMax,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ,
Position = Positionₙ⁺,
Density = ρₙ⁺,
Velocity = Velocityₙ⁺,
Expand All @@ -809,7 +804,7 @@ using LinearAlgebra
@timeit SimMetaData.HourGlass "06 NeighborLoop" NeighborLoopPerParticle!(
SimDensityDiffusion, SimViscosity, SimKernel, SimMetaData,
SimConstants, SimParticles, ParticleRanges, CellDict,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ, AccelerationMax,
NeighborCellLists, dρdtI, Acceleration, ∇Cᵢ, ∇◌rᵢ,
Position = Positionₙ⁺,
Density = ρₙ⁺,
Velocity = Velocityₙ⁺,
Expand All @@ -824,7 +819,7 @@ using LinearAlgebra

@timeit SimMetaData.HourGlass "10 Update MetaData" UpdateMetaData!(SimMetaData, dt)

@timeit SimMetaData.HourGlass "11 Update TimeStep" dt = UpdateTimeStep(AccelerationMax, SimConstants, SimKernel)
@timeit SimMetaData.HourGlass "11 Update TimeStep" dt = UpdateTimeStep(Acceleration, SimConstants, SimKernel)
end
end

Expand Down
24 changes: 20 additions & 4 deletions src/TimeStepping.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -34,20 +34,36 @@ function Δt(max_acceleration, SimulationConstants, SPHKernel)
end

"""
UpdateTimeStep(AccelerationMax, SimConstants, SimKernel)
UpdateTimeStep(Acceleration, SimConstants, SimKernel)

Computes and returns the updated time step based on maximum acceleration across all particles.

# Arguments
- `AccelerationMax`: Array of acceleration magnitudes for each particle.
- `Acceleration`: Vector of per-particle acceleration vectors.
- `SimConstants`: Struct containing simulation parameters.
- `SimKernel`: Struct containing kernel parameters.

# Returns
- The calculated adaptive time step `dt`.
"""
function UpdateTimeStep(AccelerationMax, SimConstants, SimKernel)
max_acceleration = maximum(AccelerationMax)
function UpdateTimeStep(Acceleration, SimConstants, SimKernel)
max_acceleration = zero(eltype(eltype(Acceleration)))
@no_escape begin
max_storage = @alloc(eltype(eltype(Acceleration)), 1)
max_storage[1] = max_acceleration
max_lock = Threads.SpinLock()
@inbounds Threads.@threads for i in eachindex(Acceleration)
acc_norm = norm(Acceleration[i])
if acc_norm > max_storage[1]
lock(max_lock)
if acc_norm > max_storage[1]
max_storage[1] = acc_norm
end
unlock(max_lock)
end
end
max_acceleration = max_storage[1]
end
return Δt(max_acceleration, SimConstants, SimKernel)
end

Expand Down