# ModelingToolkit.jl: Handling Output/Input Dependency in a DAE Model

**URL:** <https://discourse.julialang.org/t/modelingtoolkit-jl-handling-output-input-dependency-in-a-dae-model/126172>\
**Category:** Modelling & Simulations\
**Created:** [February 22, 2025, 3:32am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-handling-output-input-dependency-in-a-dae-model/126172 "2025-02-22T03:32:20Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![TimGyx](https://avatars.discourse-cdn.com/v4/letter/t/ecd19e/32.png) [@TimGyx](https://discourse.julialang.org/u/TimGyx)\
**Post date:** [February 11, 2026, 4:46am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-handling-output-input-dependency-in-a-dae-model/126172/5 "2026-02-11T04:46:00Z")

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Hi I am also trying to build a refrigerant cycle similar to the turbine system, and i am also using the DAE equations directly without the MTK components. When i reduce my DAE to steady state model, the NL solver can solve the system. But when i tried to solve the same steady state model using IDA solver, the solver failed to initialize even when i fed in the solution generated from NL solver as the initial condition. I am thinking this might be related to the coolprop functions i called. Is there any suggestions for building the DAE system using coolprop and include phase change scenario? I have set up this question [DAE‑safe bounding for CoolProp property calls in Julia](https://discourse.julialang.org/t/dae-safe-bounding-for-coolprop-property-calls-in-julia/135416) that contains the same problem. Thank you for your reply!

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