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Use LinearSolve routines for the residual equation rather than the original equation #46

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Merged
merged 3 commits into from
Apr 7, 2025
Merged

Use LinearSolve routines for the residual equation rather than the original equation #46

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d37331b
Use LinearSolve routines for the residual equation rather than the or…
pjaap Apr 7, 2025
cd4d3cd
Add CHANGELOG entry and bump compats
pjaap Apr 7, 2025
ced3fc7
Fix ranges of the solution vector
pjaap Apr 7, 2025
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6 changes: 6 additions & 0 deletions CHANGELOG.md
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Expand Up @@ -2,6 +2,12 @@

## next version

## v1.0.0 April 7, 2025

### Changed

- `solve` uses now the residual equation for the linear systems.

## v0.9.0 March 22, 2025

### Added
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4 changes: 2 additions & 2 deletions Project.toml
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@@ -1,7 +1,7 @@
name = "ExtendableFEM"
uuid = "a722555e-65e0-4074-a036-ca7ce79a4aed"
authors = ["Christian Merdon <merdon@wias-berlin.de>", "Patrick Jaap <patrick.jaap@wias-berlin.de>"]
version = "0.9.1"
version = "1.0.0"

[deps]
CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"
Expand All @@ -28,7 +28,7 @@ DiffResults = "1"
DocStringExtensions = "0.8,0.9"
ExampleJuggler = "2.2.1"
ExplicitImports = "1"
ExtendableFEMBase = "0.8"
ExtendableFEMBase = "1"
ExtendableGrids = "1.10.3"
ExtendableSparse = "1.5.3"
ForwardDiff = "0.10.35,1"
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108 changes: 66 additions & 42 deletions src/solvers.jl
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Expand Up @@ -258,31 +258,29 @@ function CommonSolve.solve(PD::ProblemDescription, FES::Union{<:FESpace, Vector{
end

## compute nonlinear residual
if !is_linear
fill!(residual.entries, 0)
for j in 1:length(b), k in 1:length(b)
addblock_matmul!(residual[j], A[j, k], sol[unknowns[k]])
end
residual.entries .-= b.entries
#res = A.entries * sol.entries - b.entries
for op in PD.operators
residual.entries[fixed_dofs(op)] .= 0
end
for u_off in SC.parameters[:inactive]
j = get_unknown_id(SC, u_off)
if j > 0
fill!(residual[j], 0)
end
end
if length(freedofs) > 0
nlres = norm(residual.entries[freedofs])
else
nlres = norm(residual.entries)
end
if SC.parameters[:verbosity] > 0 && length(residual) > 1
@info "sub-residuals = $(norms(residual))"
fill!(residual.entries, 0)
for j in 1:length(b), k in 1:length(b)
addblock_matmul!(residual[j], A[j, k], sol[unknowns[k]])
end
residual.entries .-= b.entries
#res = A.entries * sol.entries - b.entries
for op in PD.operators
residual.entries[fixed_dofs(op)] .= 0
end
for u_off in SC.parameters[:inactive]
j = get_unknown_id(SC, u_off)
if j > 0
fill!(residual[j], 0)
end
end
if length(freedofs) > 0
nlres = norm(residual.entries[freedofs])
else
nlres = norm(residual.entries)
end
if SC.parameters[:verbosity] > 0 && length(residual) > 1
@info "sub-residuals = $(norms(residual))"
end
end
time_final += time_assembly
allocs_final += allocs_assembly
Expand Down Expand Up @@ -349,25 +347,40 @@ function CommonSolve.solve(PD::ProblemDescription, FES::Union{<:FESpace, Vector{
linsolve.A = A.entries.cscmatrix
end
end
if !SC.parameters[:constant_rhs] || !SC.parameters[:initialized]
if length(freedofs) > 0
linsolve.b = b.entries[freedofs]
else
linsolve.b = b.entries
end

# we solve for A Δx = r
# and update x = sol - Δx
if length(freedofs) > 0
linsolve.b = residual.entries[freedofs]
else
linsolve.b = residual.entries
end
SC.parameters[:initialized] = true

## solve
push!(stats[:matrix_nnz], nnz(linsolve.A))
x = LinearSolve.solve!(linsolve)
Δx = LinearSolve.solve!(linsolve)

# x = sol.entries - Δx.u for free dofs or partial solutions
if length(freedofs) > 0
x = sol.entries[freedofs] - Δx.u
else
x = zero(Δx)
offset = 0
for u in unknowns
ndofs_u = length(view(sol[u]))
x_range = (offset + 1):(offset + ndofs_u)
x[x_range] .= view(sol[u]) .- view(Δx, x_range)
offset += ndofs_u
end
end

## check linear residual with full matrix
if length(freedofs) > 0
soltemp.entries[freedofs] .= x.u
soltemp.entries[freedofs] .= x
residual.entries .= A.entries.cscmatrix * soltemp.entries
else
residual.entries .= A.entries.cscmatrix * x.u
residual.entries .= A.entries.cscmatrix * x
end
residual.entries .-= b.entries
for op in PD.operators
Expand All @@ -386,14 +399,14 @@ function CommonSolve.solve(PD::ProblemDescription, FES::Union{<:FESpace, Vector{
## update solution (incl. damping etc.)
offset = 0
if length(freedofs) > 0
sol.entries[freedofs] .= x.u
sol.entries[freedofs] .= x
else
for u in unknowns
ndofs_u = length(view(sol[u]))
if damping > 0
view(sol[u]) .= damping * view(sol[u]) + (1 - damping) * view(x.u, (offset + 1):(offset + ndofs_u))
view(sol[u]) .= damping * view(sol[u]) + (1 - damping) * view(x, (offset + 1):(offset + ndofs_u))
else
view(sol[u]) .= view(x.u, (offset + 1):(offset + ndofs_u))
view(sol[u]) .= view(x, (offset + 1):(offset + ndofs_u))
end
offset += ndofs_u
end
Expand Down Expand Up @@ -645,17 +658,28 @@ function iterate_until_stationarity(
if !SC.parameters[:constant_matrix] || !SC.parameters[:initialized]
linsolve.A = A.entries.cscmatrix
end
if !SC.parameters[:constant_rhs] || !SC.parameters[:initialized]
linsolve.b = b.entries
end

# we solve for A Δx = r
# and update x = sol - Δx
linsolve.b = residual.entries
SC.parameters[:initialized] = true


## solve
x = LinearSolve.solve!(linsolve)
Δx = LinearSolve.solve!(linsolve)

# x = sol.entries - Δx.u ... in the entry ranges of the present unknowns
x = zero(Δx.u)
offset = 0
for u in unknowns[p]
ndofs_u = length(view(sol[u]))
x_range = (offset + 1):(offset + ndofs_u)
x[x_range] .= view(sol[u]) .- view(Δx.u, x_range)
offset += ndofs_u
end

fill!(residual.entries, 0)
mul!(residual.entries, A.entries.cscmatrix, x.u)
mul!(residual.entries, A.entries.cscmatrix, x)
residual.entries .-= b.entries
for op in PD.operators
for dof in fixed_dofs(op)
Expand All @@ -670,9 +694,9 @@ function iterate_until_stationarity(
for u in unknowns[p]
ndofs_u = length(view(sol[u]))
if damping > 0
view(sol[u]) .= damping * view(sol[u]) + (1 - damping) * view(x.u, (offset + 1):(offset + ndofs_u))
view(sol[u]) .= damping * view(sol[u]) + (1 - damping) * view(x, (offset + 1):(offset + ndofs_u))
else
view(sol[u]) .= view(x.u, (offset + 1):(offset + ndofs_u))
view(sol[u]) .= view(x, (offset + 1):(offset + ndofs_u))
end
offset += ndofs_u
end
Expand Down
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