# DataDrivenDiffEq.jl - Package

**URL:** https://discourse.julialang.org/t/datadrivendiffeq-jl-package/107209
**Category:** New to Julia
**Tags:** question, package
**Created:** [December 6, 2023, 10:08am UTC](https://discourse.julialang.org/t/datadrivendiffeq-jl-package/107209 "2023-12-06T10:08:31Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![npsasikumar](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/npsasikumar/32/43609_2.png) [@npsasikumar](https://discourse.julialang.org/u/npsasikumar)
#### Post date: [December 6, 2023, 10:08am UTC](https://discourse.julialang.org/t/datadrivendiffeq-jl-package/107209/1 "2023-12-06T10:08:31Z")

</div>

I am new to Julia, and I am a researcher in mathematics working with the synchronization of nonlinear dynamical systems. While implementing koopman\_res as in the nonlinear\_forced.jl the [link](https://github.com/SciML/DataDrivenDiffEq.jl/blob/master/lib/DataDrivenDMD/test/nonlinear_forced.jl): for my system, its showing the error : Test threw exception  
Expression: ≈(get\_inputmap(koopman\_res), [0, 1.0, 0.0, 0.0, 0.0], atol = 0.1)  
DimensionMismatch: dimensions must match: a has dims (Base.OneTo(0), Base.OneTo(0)), b has dims (Base.OneTo(5),), mismatch at 1.

When I use println(get\_inputmap(koopman\_res), the result is: Matrix{Any}(undef, 0, 0)

Please do suggest identifying the dimension of the function “get\_inputmap(koopman\_res)”.  
Thank you in advance.