# ODESystem not handeling dynamic parameters

**URL:** https://discourse.julialang.org/t/odesystem-not-handeling-dynamic-parameters/124118
**Category:** Modelling & Simulations
**Created:** [December 23, 2024, 12:11pm UTC](https://discourse.julialang.org/t/odesystem-not-handeling-dynamic-parameters/124118 "2024-12-23T12:11:06Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Sushrut\_Deshpande](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sushrut_deshpande/32/52754_2.png) [@Sushrut\_Deshpande](https://discourse.julialang.org/u/Sushrut_Deshpande)
#### Post date: [December 23, 2024, 12:11pm UTC](https://discourse.julialang.org/t/odesystem-not-handeling-dynamic-parameters/124118/1 "2024-12-23T12:11:06Z")

</div>

Hello,

I have a toy problem where I have a parameter that depends on time

```julia
using ModelingToolkit, DifferentialEquations
using ModelingToolkit: t_nounits as t, D_nounits as D

function test(;name)
    vars = @variables begin
        x(t)
    end
    para = @parameters begin
        α(t)
    end
    eqs = [
        D(x) ~ α
    ]
    ODESystem(eqs,t,vars,para,name=name)
end
@named model = test()
sys = structural_simplify(model)
para = [sys.α => cos(t)]
u0 = [sys.x => 1]
tspan = (0,2π)
prob = ODEProblem(sys,u0,tspan,para)
sol = solve(prob)

```

The solution I get after solving does not consider the parameter to be dynamic.  
Here it will fix `α` = `cos(0)` = 1 for the entire time span.