-
-
Notifications
You must be signed in to change notification settings - Fork 199
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #1037 from JuliaDiffEq/daeinit
Basic DAE Initialization
- Loading branch information
Showing
8 changed files
with
189 additions
and
11 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,93 @@ | ||
| abstract type DAEInitializationAlgorithm end | ||
|
|
||
| struct BrownFullBasicInit{T} <: DAEInitializationAlgorithm | ||
| abstol::T | ||
| end | ||
| BrownFullBasicInit() = BrownFullBasicInit(1e-10) | ||
|
|
||
| function initialize_dae!(integrator, u, du, differential_vars, alg::BrownFullBasicInit, ::Val{true}) | ||
| @unpack p, t, f = integrator | ||
|
|
||
| tmp = get_tmp_cache(integrator)[1] | ||
| f(tmp, du, u, p, t) | ||
|
|
||
| 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 | ||
|
|
||
| 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 | ||
|
|
||
| r = nlsolve(nlequation, zero(u)) | ||
|
|
||
| for i in 1:length(u) | ||
| if differential_vars[i] | ||
| du[i] = r.zero[i] | ||
| else | ||
| u[i] = r.zero[i] | ||
| end | ||
| end | ||
|
|
||
| return | ||
| end | ||
|
|
||
| function initialize_dae!(integrator, _u, _du, differential_vars, alg::BrownFullBasicInit, ::Val{false}) | ||
| @unpack p, t, f = integrator | ||
|
|
||
| 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 | ||
|
|
||
| if _u isa Number && _du isa Number | ||
| # This doesn't fix static arrays! | ||
| u = [_u] | ||
| du = [_du] | ||
| else | ||
| u = _u | ||
| du = _du | ||
| end | ||
|
|
||
| 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 | ||
|
|
||
| r = nlsolve(nlequation, zero(u)) | ||
|
|
||
| for i in 1:length(u) | ||
| if differential_vars[i] | ||
| du[i] = r.zero[i] | ||
| else | ||
| u[i] = r.zero[i] | ||
| end | ||
| end | ||
|
|
||
| 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 | ||
|
|
||
| return | ||
| end |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,73 @@ | ||
| using OrdinaryDiffEq, StaticArrays, Test | ||
|
|
||
| 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 | ||
|
|
||
| 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()) | ||
|
|
||
| @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 | ||
|
|
||
| integrator = init(prob, DImplicitEuler()) | ||
|
|
||
| @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 | ||
|
|
||
| # 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 | ||
|
|
||
| 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()) | ||
|
|
||
| @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 | ||
|
|
||
| f = function (du,u,p,t) | ||
| du - u | ||
| end | ||
|
|
||
| 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()) | ||
|
|
||
| @test integrator.cache.du ≈ 1.0 atol=1e-9 | ||
|
|
||
| f = function (du,u,p,t) | ||
| du .- u | ||
| end | ||
|
|
||
| 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()) | ||
|
|
||
| @test integrator.cache.du[1] ≈ 1.0 atol=1e-9 | ||
| @test integrator.cache.du[2] ≈ 1.0 atol=1e-9 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters