# MTK - structurally singular initialization?

**URL:** https://discourse.julialang.org/t/mtk-structurally-singular-initialization/136771
**Category:** Modelling & Simulations
**Created:** [April 18, 2026, 8:06pm UTC](https://discourse.julialang.org/t/mtk-structurally-singular-initialization/136771 "2026-04-18T20:06:40Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![BLI](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bli/32/37206_2.png) [@BLI](https://discourse.julialang.org/u/BLI)
#### Post date: [April 18, 2026, 8:06pm UTC](https://discourse.julialang.org/t/mtk-structurally-singular-initialization/136771/1 "2026-04-18T20:06:40Z")

</div>

I have a somewhat complex model constructed from my own components. Doing `mtkcompile` produces a system with 18 unknowns and 18 equations: 14 DEs and 4 AEs.

When I create the ODEProblem, I am told:

```julia-auto
Warning: The initialization system is structurally singular. Guess values may significantly affect the initial values of the ODE. The problematic variables are SymbolicUtils.BasicSymbolicImpl.var"typeof(BasicSymbolicImpl)"{SymReal}[intake₊b₊pˍt(t)].
│ 
│ Note that the identification of problematic variables is a best-effort heuristic

```

Yet, the initialization seems to work:

```julia-auto
ODEProblem with uType Vector{Float64} and tType Float64. In-place: true
Initialization status: FULLY_DETERMINED
Non-trivial mass matrix: true
timespan: (0.0, 50.0)
u0: 18-element Vector{Float64}:
      1.0
      1.0e-6
      0.0
      0.0
      0.0
      1.0e-6
      2.30782125e6
      0.0
      0.0
 100000.0
      1.0e-6
  39023.93516845321
      0.0
      1.0e-6
 199391.5
      0.0
      1.0e-6
      0.0

```

When I try to solve the problem using Rodas5P, there is a solution, and the solution makes sense.

**Question** : How can I figure out why there is a report about “singular initialization problem”? And what do I need to do to fix/get rid of this warning?