Support blocked linear systems. - #73
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After long dicussion with Gemini (August 2026), I disregarded all advice it gave, and figured out that one of the two issues were: - Since we use SNES and setCTX in the setFunction and setJacobian operations, we can't use the classical python-esque replacement of compiled forms. This invalidated the recompute for non-linear problems. Another issue covered by Claude (in another PR spawned by @finsberg) is that `u` was added as its own dependency if the problem was truely nonlinear. This is now fixed. Added tests to check this.
…result of the replay.
…f my own thoughts/changes: -As pyadjoint eagerly creates new functions, we have to recompile the forms (maybe we should use the data independent form creators, would align with redoxnics ideas). - Add convenience function to get arguments sorted by part. - Minor bug-fixes on using PETSc/non-PETSc vectors. - Correct usage of idx in evaluate_hessian_component. idx only relates to inputs. Output is in control space (always). Added check of this. - Instead of recreating vectors to attach to the tlm/adjoint solvers, instead use the vector that is created once and zero it out. Better for evyerone.
- Using compute_adjoint action on problems that mixes ufl.MixedFunctionSpace arguments and non-mixed arguments is a bad idea (looking at you prepare_hessian). Therefore we use the trick of creating a Lagrangian and differentiate it. - Various nested type-hinting to make the recursive code mypy friendly. - Action on a form does not like lists, only place that has a bit of split handling at the momment (_compute_residual).
Simplify the code for adjoint in linear solver.
Time-distributed control + blocked rewrite.
…o let adjoint_solver have its own internal state and then copy to correct array post solve.
finsberg
self-requested a review
August 28, 2026 07:31
finsberg
approved these changes
Aug 28, 2026
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Summary
Adds support for blocked forms
[[a00, ..., a0N], ...., [aN0, ..., aNN]]as input to LinearProblem.Bug-fixes for other problems
Various lessons learnt along the way
-As pyadjoint eagerly creates new functions, we have to recompile the forms (maybe we should use the data independent form creators, would align with redoxnics ideas).