# Passing values from an array in ModeliingToolkit framework

**URL:** <https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976>\
**Category:** General Usage\
**Tags:** question, modelingtoolkit\
**Created:** [November 29, 2022, 6:00am UTC](https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976 "2022-11-29T06:00:05Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Rohan\_Rajagopal](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rohan_rajagopal/32/34183_2.png) [@Rohan\_Rajagopal](https://discourse.julialang.org/u/Rohan_Rajagopal)\
**Post date:** [November 29, 2022, 6:00am UTC](https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976/1 "2022-11-29T06:00:05Z")

</div>

I have a previously solved system (dt=1/200, ~adaptive=false, tspan = (0, 50)), stored as an array say 'A.' I want to use these values in another modelingtoolkit setup.

A is essentially like a sinusoidal signal.

```julia
eqs = [ 
    D(r) ~ r*(1 - r^2)*r
    D(θ) ~ 2 + "Values_from_A"
]

```

Does anyone have any suggestions, I thought I could do something like

```julia
data_time_convert(t) = model_a_encoder_1_layers(data_mod_signal)[1, trunc(Int64, (t%50)*200) + 1]'
@register_symbolic data_time_convert(t)

```

Deeply appreciate any suggestions.

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [November 29, 2022, 8:29am UTC](https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976/2 "2022-11-29T08:29:15Z")

</div>

Make `A(t)` a time-dependent parameter and pass in the interpolation to generate `A(t)` as one of the parameter pieces.

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<div class="post-metadata">

**Author:** ![Rohan\_Rajagopal](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rohan_rajagopal/32/34183_2.png) [@Rohan\_Rajagopal](https://discourse.julialang.org/u/Rohan_Rajagopal)\
**Post date:** [November 30, 2022, 8:55am UTC](https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976/3 "2022-11-30T08:55:36Z")

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Hey, thanks for the suggestion, however, placing A(t) in the equations throws the following error. (I have defined A(t) as a variable.) As the following,

```julia
@variables A(t)

```

```julia
eqs = [ 
    D(r) ~ r*(1 - r^2)*r
    D(θ) ~ 2 + A(t)
]

Sym (A(t)) is not callable. Use @syms (A(t))(var1, var2,...) to create it as a callable.

```

Or, I have horribly misunderstood your suggestions.

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [December 2, 2022, 2:35pm UTC](https://discourse.julialang.org/t/passing-values-from-an-array-in-modeliingtoolkit-framework/90976/4 "2022-12-02T14:35:46Z")

</div>

```julia
@variables A(t)
eqs = [ 
    D(r) ~ r*(1 - r^2)*r
    D(θ) ~ 2 + A
]

```