# ModelingToolkit.jl trows error: statement is ambigous

**URL:** <https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045>\
**Category:** Modelling & Simulations\
**Created:** [June 1, 2022, 10:26am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045 "2022-06-01T10:26:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Davide\_Degavi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/davide_degavi/32/36808_2.png) [@Davide\_Degavi](https://discourse.julialang.org/u/Davide_Degavi)\
**Post date:** [June 1, 2022, 10:26am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045/1 "2022-06-01T10:26:38Z")

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Hi everyone, I’m new to Julia so maybe the problem that I’ve anecountered is preatty trivial.  
Basically I have two main problem with the simple symbolic equation expressing the kinetic energy of a rigid body satellite.

- FIrst: I don’t know how to multiplicate a symbolic value by a scalar one.
- Second: the code part with: omega’_(R_Ic\*R’)\*omega trows an error telling me that it is ambigous and here I got stucked and I’ve not found a solution so far.

Hereafter I share my code. Thx in advance for any answer.  
Davide

```julia
using DifferentialEquations
using ModelingToolkit

@parameters I[1:3,1:3] mc[1,1] mu[1,1] 
@variables t r[1:3,1](t) angle[1:3,1](t)

D = Differential(t)

R= [cos(angle[1]).*cos(angle[3])-cos(angle[2]).*sin(angle[1]).*sin(angle[3]) sin(angle[1]).*cos(angle[3])+cos(angle[2]).*cos(angle[1]).*sin(angle[3]) sin(angle[2]).*sin(angle[3])
        -cos(angle[1]).*sin(angle[3])-cos(angle[2]).*sin(angle[1]).*cos(angle[3]) -sin(angle[1]).*sin(angle[3])+cos(angle[2]).*cos(angle[1]).*cos(angle[3]) sin(angle[2]).*cos(angle[3])
        sin(angle[2]).*sin(angle[3]) -sin(angle[2]).*cos(angle[1]) cos(angle[2])]

d_angle = D(angle)
v = D(r)

omega = [d_angle[2].*cos(angle[1])+d_angle[3].*sin(angle[2]).*sin(angle[1])
        d_angle[2].*sin(angle[1])-d_angle[3].*sin(angle[2]).*cos(angle[1])
        d_angle[1]+d_angle[3].*cos(angle[2])]

Tc = 0.5 *v'*(mc*v) + 0.5*omega'*(R*Ic*R')*omega

```

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<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:** [June 1, 2022, 10:57am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045/2 "2022-06-01T10:57:03Z")

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What’s the error?

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<div class="post-metadata">

**Author:** ![Davide\_Degavi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/davide_degavi/32/36808_2.png) [@Davide\_Degavi](https://discourse.julialang.org/u/Davide_Degavi)\
**Post date:** [June 1, 2022, 11:22am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045/3 "2022-06-01T11:22:00Z")

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I have two different errors:

- The First one when I insert in the terminal the following part of the equation: 0.5 \*v’ \* (mc \* v). And the error I get is: MethodError: no method matching \*(::Float64, ::Symbolics.ArrayOp{Matrix{Num}})
- The second one I get is: MethodError: \*(::LinearAlgebra.Adjoint{Num, Vector{Num}}, ::Symbolics.Arr{Num, 2}) is ambiguous.  
when I write in the terminal the following: omega’ \* (R \* Ic \* R’ ) \* omega

Hope I was clear.

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<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:** [June 1, 2022, 11:56am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-trows-error-statement-is-ambigous/82045/4 "2022-06-01T11:56:25Z")

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What’s the error message?