Cannot disable Jacobian sparsity pattern checking

[hersle]

I want to solve an ODE with an implicit solver and sparse Jacobian. LinearSolve docs hint at setting check_pattern = false for a speedup if the sparsity pattern is constant. This check allocates and shows up in the solve flamegraph:

using ModelingToolkit, OrdinaryDiffEqRosenbrock, LinearSolve
D, t = ModelingToolkit.D_nounits, ModelingToolkit.t_nounits
@variables x(t) y(t)
@named M = System([D(x) ~ x + y, D(y) ~ x], t)
M = mtkcompile(M)
prob = ODEProblem(M, [x => 1.0, y => 1.0], (0.0, 1.0); jac = true, sparse = true)
@profview sol = solve(prob, Rodas5P(linsolve = KLUFactorization(check_pattern = true)); adaptive = false, dt = 1e-6, save_everystep = false)

Should it then work to solve the ODE as in the last line here?

sol = solve(prob, Rodas5P(linsolve = KLUFactorization(check_pattern = true))) # works
sol = solve(prob, Rodas5P(linsolve = KLUFactorization(check_pattern = false))) # fails

The last line fails with

ERROR: DimensionMismatch:
Stacktrace:
  [1] klu!(K::LinearSolveSparseArraysExt.KLU.KLUFactorization{…}, nzval::Vector{…}; check::Bool, allowsingular::Bool)
    @ LinearSolveSparseArraysExt.KLU C:\Users\herma\.julia\dev\LinearSolve\src\KLU\klu.jl:651
  [2] klu!
    @ C:\Users\herma\.julia\dev\LinearSolve\src\KLU\klu.jl:649 [inlined]      
  [3] solve!(cache::LinearSolve.LinearCache{…}, alg::KLUFactorization; kwargs::@Kwargs{…})
    @ LinearSolveSparseArraysExt C:\Users\herma\.julia\dev\LinearSolve\ext\LinearSolveSparseArraysExt.jl:292
  [4] solve!
    @ C:\Users\herma\.julia\dev\LinearSolve\ext\LinearSolveSparseArraysExt.jl:277 [inlined]
  [5] #solve!#21
    @ C:\Users\herma\.julia\dev\LinearSolve\src\common.jl:441 [inlined]       
  [6] solve!
    @ C:\Users\herma\.julia\dev\LinearSolve\src\common.jl:440 [inlined]       
  [7] #dolinsolve#2
    @ C:\Users\herma\.julia\packages\OrdinaryDiffEqDifferentiation\TKWRC\src\linsolve_utils.jl:30 [inlined]
  [8] dolinsolve
    @ C:\Users\herma\.julia\packages\OrdinaryDiffEqDifferentiation\TKWRC\src\linsolve_utils.jl:5 [inlined]
  [9] perform_step!(integrator::OrdinaryDiffEqCore.ODEIntegrator{…}, cache::OrdinaryDiffEqRosenbrock.RosenbrockCache{…}, repeat_step::Bool)
    @ OrdinaryDiffEqRosenbrock C:\Users\herma\.julia\packages\OrdinaryDiffEqRosenbrock\L1JuA\src\rosenbrock_perform_step.jl:1363

[hersle]

I suspect what happens is that KLUFactorization stores some "null factorization" at construction, and errors when it encounters the true ODE Jacobian for the first time?

[ChrisRackauckas]

Is this handled?

[hersle]

Yep, forgot to close.