Plotting Implicit Functions using ImplicitEquations.jl

Specific Domains Visualization
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21

Can something like this be put into build_function?

22

yes. Any symbolic statement or arrays (of arrays or sparse matrices or etc.) of symbolic statements can.

1 Like
23

I thought it should be. I can’t tell now if there is a problem with what I’m trying to do, or just with syntax

@variables x y u μ t Δtx Δty
@derivatives δx'~x δy'~y δu'~u δμ'~μ

#declared variables and derivatives, unless I also need something in the let ex= row, to assign variables

let ex  = "Δtx*(δu(sqrt(u))*δx(x^2+144)) +Δty*(δμ(sqrt(μ))*δy(y^2+144)))";
    func_ex= build_function(expand_derivatives(Δtx*(δu(sqrt(u))*δx(x^2+144) +Δty*(δμ(sqrt(μ))*δy(y^2+144))))  
                  @eval vb(x,y,Δtx,Δty) = ($func_ex)(x,y,Δx,Δy)
              end
24

That’s not real syntax. You never declared the variables. You might want to look at the documentation or Mason’s example.

25

I edited my post, not sure if I found the issue, sorry it wasn’t an MWE

26 
@variable x y t
@derivatives δx'~x δy'~y δt'~t

v(x,y,t)=sqrt(x^2+144)*+sqrt(y^2+144)
let ex  =  Differential(x)(v(x, y,t));
    func_ex= build_function(expand_derivatives(δtx*(δu(sqrt(u))*δx(x^2+144) +δty*(δμ(sqrt(μ))*δy(y^2+144)))))  
        @eval ∂xf(x, y,t) = ($func_ex)(x,y,t)
              end
27

Again, that’s not the syntax for build_function.

28

I think I have something that’s closer.

v(x,y,t)=sqrt(x^2+144)*+sqrt(y^2+144)
let ex  =  Differential(x)(v(x, y,t));
    func_ex= build_function(expand_derivatives(δtx*(δu(sqrt(u))*δx(x^2+144) +δty*(δμ(sqrt(μ))*δy(y^2+144))))x,y,t)  
    @eval δxf(x, y,t) = ($func_ex)(x,y,t)
              end
29

How would I plot the original function on the same graph?

plot!(f(x,y))