Array of components #2674
Comments
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@ven-k is the array form documented? |
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Yes it's the examples here: https://docs.sciml.ai/ModelingToolkit/stable/basics/MTKModel_Connector/#What-can-an-MTK-Model-definition-have? The relevant bits (from ModelC example): @mtkmodel ModelC begin
@structural_parameters begin
N = 2
end
:
@components begin
model_a = ModelA(; k_array)
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
:
endFor |
|
Thanks for answer! Useful, but it only addresses part of my question, and misses the most important part (marked with red):
Creation of vectors:
The example you refer to illustrates how a vector of models, `model_array_a` and `model_array_b` can be created. I missed that. Yingbo has used a third way, e.g., `model_array_c[1:N] = ModelA()` in his presentations. Perhaps this third way is only suitable when all model instantiations are equal...
Reference to vector elements:
You write:
The relevant bits (from ModelC example):
@mtkmodel ModelC begin
@structural_parameters begin
N = 2
end
:
@components begin
model_a = ModelA(; k_array)
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
:
end
For @nAmed model_c = ModelC() ,the subcomponents can be then accessed as model_c.model_array_a_1, model_c.model_array_a_2 and so on.
This is useful. However, it doesn't answer my question, which was: how do I address the elements of, say, model_a within the ModelC definition. In other words, suppose I add:
...
@components begin
model_a = ModelA(; k_array)
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
@equations begin
for i in 1:N
model_array_a[i].k ~ 3
end
end
:
end
OK – not a perfect example since `k` is a parameter; in my case it would be a variable.
What I have inserted in red above does not work. Should it be `model_array_a_i` instead? Or something else?
BR,
Bernt
…________________________________
From: Christopher Rackauckas ***@***.***>
Sent: Monday, April 29, 2024 8:04 AM
To: SciML/ModelingToolkit.jl ***@***.***>
Cc: Bernt Lie ***@***.***>; Author ***@***.***>
Subject: Re: [SciML/ModelingToolkit.jl] Array of components (Issue #2674)
Closed #2674<#2674> as completed.
—
Reply to this email directly, view it on GitHub<#2674 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AM5VM72TFKURHHYMTHC6PTLY7XPFLAVCNFSM6AAAAABG4EHJVWVHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJSGYZTOOJSGQZTCMQ>.
You are receiving this because you authored the thread.
T
|
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To make it simpler, consider my slightly modified code from the documentation, where my changes are highlighted in *red*:
using ModelingToolkit
using ModelingToolkit: t
@mtkmodel ModelA begin
@parameters begin
k
k_array[1:2]
end
end
@mtkmodel ModelB begin
@parameters begin
p1 = 1.0, [description = "Parameter of ModelB"]
p2 = 1.0, [description = "Parameter of ModelB"]
end
end
@mtkmodel ModelC begin
# @ICON "https://github.com/SciML/SciMLDocs/blob/main/docs/src/assets/logo.png"
@Constants begin
c::Int = 1, [description = "Example constant."]
end
@structural_parameters begin
f = sin
N = 2
end
begin
v_var = 1.0
end
@variables begin
v(t) = v_var
v_array(t)[1:2, 1:3]
v_for_defaults(t)
end
@extend ModelB(; p1)
@components begin
model_a = ModelA(; k_array = [1, 2])
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
@equations begin
model_a.k ~ f(v)
model_array_a[1:N].k ~ f(v)
end
@defaults begin
v_for_defaults => 2.0
end
end
;
The addition of model_array_a[1:N].k ~ f(v) causes the error message below [same error message if I write .~ ]::
@mtkbuild modelc = ModelC()
type Array has no field k Stacktrace: [1] getproperty @ .\Base.jl:37<https://untitled+.vscode-resource.vscode-cdn.net/Base.jl:37> [inlined] [2] #__ModelC__#74 @ C:\Users\Bernt\.julia\packages\UnPack\EkESO\src\UnPack.jl:1396 [inlined] [3] __ModelC__(; name::Symbol, v_array::Nothing, p1::Nothing, N::Int64, model_array_a__k::Nothing, f::typeof(sin), v::Nothing, model_a__k_array::Nothing, v_for_defaults::Nothing, model_array_b__k::Nothing) @ Main .\none:0<https://untitled+.vscode-resource.vscode-cdn.net/none:0> [4] (::ModelingToolkit.Model{typeof(__ModelC__), Dict{Symbol, Any}})(; ***@***.***{name::Symbol}) @ ModelingToolkit C:\Users\Bernt\.julia\packages\ModelingToolkit\QP8aH\src\systems\model_parsing.jl:25 [5] top-level scope @ C:\Users\Bernt\.julia\packages\ModelingToolkit\QP8aH\src\systems\abstractsystem.jl:1396
…________________________________
From: Bernt Lie ***@***.***>
Sent: Monday, April 29, 2024 10:25 AM
To: SciML/ModelingToolkit.jl ***@***.***>; SciML/ModelingToolkit.jl ***@***.***>
Cc: Author ***@***.***>
Subject: Re: [SciML/ModelingToolkit.jl] Array of components (Issue #2674)
Thanks for answer! Useful, but it only addresses part of my question, and misses the most important part (marked with red):
Creation of vectors:
The example you refer to illustrates how a vector of models, `model_array_a` and `model_array_b` can be created. I missed that. Yingbo has used a third way, e.g., `model_array_c[1:N] = ModelA()` in his presentations. Perhaps this third way is only suitable when all model instantiations are equal...
Reference to vector elements:
You write:
The relevant bits (from ModelC example):
@mtkmodel ModelC begin
@structural_parameters begin
N = 2
end
:
@components begin
model_a = ModelA(; k_array)
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
:
end
For @nAmed model_c = ModelC() ,the subcomponents can be then accessed as model_c.model_array_a_1, model_c.model_array_a_2 and so on.
This is useful. However, it doesn't answer my question, which was: how do I address the elements of, say, model_a within the ModelC definition. In other words, suppose I add:
...
@components begin
model_a = ModelA(; k_array)
model_array_a = [ModelA(; k = i) for i in 1:N]
model_array_b = for i in 1:N
k = i^2
ModelA(; k)
end
end
@equations begin
for i in 1:N
model_array_a[i].k ~ 3
end
end
:
end
OK – not a perfect example since `k` is a parameter; in my case it would be a variable.
What I have inserted in red above does not work. Should it be `model_array_a_i` instead? Or something else?
BR,
Bernt
________________________________
From: Christopher Rackauckas ***@***.***>
Sent: Monday, April 29, 2024 8:04 AM
To: SciML/ModelingToolkit.jl ***@***.***>
Cc: Bernt Lie ***@***.***>; Author ***@***.***>
Subject: Re: [SciML/ModelingToolkit.jl] Array of components (Issue #2674)
Closed #2674<#2674> as completed.
—
Reply to this email directly, view it on GitHub<#2674 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AM5VM72TFKURHHYMTHC6PTLY7XPFLAVCNFSM6AAAAABG4EHJVWVHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJSGYZTOOJSGQZTCMQ>.
You are receiving this because you authored the thread.
T
|
|
(My color coding disappeared when transferring my e-mail to the GitHub system...) |
How can I iterate over that array of components? Eg. I can write connect(model_c.model_array_a_1, other_component)
connect(model_c.model_array_a_2, other_component)
connect(model_c.model_array_a_3, other_component)
connect(model_c.model_array_a_4, other_component)but that's terrible. Can I somehow write a for loop? |
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This does not work for me. MWE: using ModelingToolkit # v9.48.0
using ModelingToolkit: t_nounits as t
@mtkmodel MyComponent begin
@variables begin
x(t)
end
@equations begin
x ~ 10
end
end
@mtkmodel Moo begin
@components begin
some_comp = MyComponent()
comp_array = [MyComponent() for i in 1:4]
end
end
@named moo = Moo()
moo.some_comp # works
moo.comp_array_1 # works
moo.comp_array # ArgumentError: System moo: variable comp_array does not existThis is the same problem highlighted in @B-LIE's comment above (#2674 (comment)) EDIT: first version accidentally used |
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The component-array is splat before adding them as subsystems. So Note that |
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Sounds good! Is there any reason why we couldn't have |
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ODESystem constructor doesn't accept Vector{ODESystem} (for subsystem) as input. Also, @mtkmodel Moo begin
@components begin
some_comp = MyComponent()
comp_array = [MyComponent() for i in 1:4]
end
@equations begin
[connect(comp_array[i], some_comp) for i in 1:4]
end
end
comp_array = [getproperty(moo, Symbol(:comp_array_, i)) for i in 1:4]Maybe there can be a helper function to access it. But I fear it will have many non-obvious failing edge cases. If I can come up with a reliable one, I'll add. |
That looks like a complicated change indeed. For context, I wanted to have a component with N connectors. In that case, the using ModelingToolkit
using ModelingToolkit: t_nounits as t
@mtkmodel MyConnector begin
@variables begin
x(t)
end
end
@mtkmodel MilkTank begin
@components begin
connections = [MyConnector() for i in 1:4]
end
end
@mtkmodel Farm begin
@components begin
m1 = MilkTank()
m2 = MilkTank()
end
@equations begin
# (sorry for the meaningless example)
[connect(co1, co2) for (co1, co2) in zip(m1.connections, m2.connections)]...
end
end
@named farm = Farm() # System m1: variable connections does not existBut on further investigation, stream connectors look like a better solution to my problem, so I don't need multiple connectors. Thank you for the input! |
Is there an example of how to use arrays of components in the documentation❓
From a presentation, I've seen the the syntax:
I don't know if this is a standard notation or not. I've tried to use it, but have problems when I add equations where the instances have fields, such...
would not work.
However,
would work.
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