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Original file line number | Diff line number | Diff line change |
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abstract type DAEInitializationAlgorithm end | ||
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struct BrownFullBasicInit{T} <: DAEInitializationAlgorithm | ||
abstol::T | ||
end | ||
BrownFullBasicInit() = BrownFullBasicInit(1e-10) | ||
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function initialize_dae!(integrator, u, du, differential_vars, alg::BrownFullBasicInit, ::Val{true}) | ||
@unpack p, t, f = integrator | ||
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tmp = get_tmp_cache(integrator)[1] | ||
f(tmp, du, u, p, t) | ||
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if integrator.opts.internalnorm(tmp,t) <= alg.abstol | ||
return | ||
elseif differential_vars === nothing | ||
error("differential_vars must be set for DAE initialization to occur. Either set consistent initial conditions or differential_vars") | ||
end | ||
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nlequation = (out, x) -> begin | ||
for i in 1:length(x) | ||
if differential_vars[i] | ||
du[i] = x[i] | ||
else | ||
u[i] = x[i] | ||
end | ||
end | ||
f(out, du, u, p, t) | ||
end | ||
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r = nlsolve(nlequation, zero(u)) | ||
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for i in 1:length(u) | ||
if differential_vars[i] | ||
du[i] = r.zero[i] | ||
else | ||
u[i] = r.zero[i] | ||
end | ||
end | ||
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return | ||
end | ||
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function initialize_dae!(integrator, _u, _du, differential_vars, alg::BrownFullBasicInit, ::Val{false}) | ||
@unpack p, t, f = integrator | ||
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if integrator.opts.internalnorm(f(_du, _u, p, t),t) <= alg.abstol | ||
return | ||
elseif differential_vars === nothing | ||
error("differential_vars must be set for DAE initialization to occur. Either set consistent initial conditions or differential_vars") | ||
end | ||
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if _u isa Number && _du isa Number | ||
# This doesn't fix static arrays! | ||
u = [_u] | ||
du = [_du] | ||
else | ||
u = _u | ||
du = _du | ||
end | ||
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nlequation = (out,x) -> begin | ||
for i in 1:length(x) | ||
if differential_vars[i] | ||
du[i] = x[i] | ||
else | ||
u[i] = x[i] | ||
end | ||
end | ||
out .= f(du, u, p, t) | ||
end | ||
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r = nlsolve(nlequation, zero(u)) | ||
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for i in 1:length(u) | ||
if differential_vars[i] | ||
du[i] = r.zero[i] | ||
else | ||
u[i] = r.zero[i] | ||
end | ||
end | ||
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if _u isa Number && _du isa Number | ||
# This doesn't fix static arrays! | ||
integrator.u = first(u) | ||
integrator.cache.du = first(du) | ||
else | ||
integrator.u = u | ||
integrator.cache.du = du | ||
end | ||
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return | ||
end |
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Original file line number | Diff line number | Diff line change |
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using OrdinaryDiffEq, StaticArrays, Test | ||
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f = function (out,du,u,p,t) | ||
out[1] = - 0.04u[1] + 1e4*u[2]*u[3] - du[1] | ||
out[2] = + 0.04u[1] - 3e7*u[2]^2 - 1e4*u[2]*u[3] - du[2] | ||
out[3] = u[1] + u[2] + u[3] - 1.0 | ||
end | ||
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u₀ = [1.0, 0, 0] | ||
du₀ = [0.0, 0.0, 0.0] | ||
tspan = (0.0,100000.0) | ||
differential_vars = [true,true,false] | ||
prob = DAEProblem(f,du₀,u₀,tspan,differential_vars=differential_vars) | ||
integrator = init(prob, DABDF2()) | ||
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@test integrator.cache.du[1] ≈ -0.04 atol=1e-9 | ||
@test integrator.cache.du[2] ≈ 0.04 atol=1e-9 | ||
@test integrator.u[3] ≈ 0.0 atol=1e-9 | ||
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integrator = init(prob, DImplicitEuler()) | ||
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@test integrator.cache.du[1] ≈ -0.04 atol=1e-9 | ||
@test integrator.cache.du[2] ≈ 0.04 atol=1e-9 | ||
@test integrator.u[3] ≈ 0.0 atol=1e-9 | ||
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# Need to be able to find the consistent solution of this problem, broken right now | ||
# analytical solution: | ||
# u[1](t) -> cos(t) | ||
# u[2](t) -> -sin(t) | ||
# u[3](t) -> 2cos(t) | ||
f = function (out,du,u,p,t) | ||
out[1] = du[1] - u[2] | ||
out[2] = du[2] + u[3] - cos(t) | ||
out[3] = u[1] - cos(t) | ||
end | ||
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u₀ = [1.0, 0.0, 0.0] | ||
du₀ = [0.0, 0.0, 0.0] | ||
tspan = (0.0,1.0) | ||
differential_vars = [true, true, false] | ||
prob = DAEProblem(f,du₀,u₀,tspan,differential_vars=differential_vars) | ||
integrator = init(prob, DABDF2()) | ||
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@test integrator.cache.du[1] ≈ 0.0 atol=1e-9 | ||
@test_broken integrator.cache.du[2] ≈ -1.0 atol=1e-9 | ||
@test_broken integrator.u[3] ≈ 2.0 atol=1e-9 | ||
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f = function (du,u,p,t) | ||
du - u | ||
end | ||
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u₀ = 1.0 | ||
du₀ = 0.0 | ||
tspan = (0.0,1.0) | ||
differential_vars = [true] | ||
prob = DAEProblem(f,du₀,u₀,tspan,differential_vars=differential_vars) | ||
integrator = init(prob, DABDF2()) | ||
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@test integrator.cache.du ≈ 1.0 atol=1e-9 | ||
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f = function (du,u,p,t) | ||
du .- u | ||
end | ||
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u₀ = SA[1.0, 1.0] | ||
du₀ = SA[0.0, 0.0] | ||
tspan = (0.0,1.0) | ||
differential_vars = [true, true] | ||
prob = DAEProblem(f,du₀,u₀,tspan,differential_vars=differential_vars) | ||
integrator = init(prob, DABDF2()) | ||
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@test integrator.cache.du[1] ≈ 1.0 atol=1e-9 | ||
@test integrator.cache.du[2] ≈ 1.0 atol=1e-9 |
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