# What does @\_## mean in @code\_warntype (and other questions)?

**URL:** <https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360>\
**Category:** General Usage\
**Tags:** code\_warntype\
**Created:** [May 2, 2022, 10:16am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360 "2022-05-02T10:16:08Z")\
**Posts on this page:** 19\
**Page:** 1

<div class="post-metadata">

**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 10:16am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/1 "2022-05-02T10:16:08Z")

</div>

Hello,

I’m a very basic Julia user working on a model simulating a food web and fishing. The model works but I need to decrease the run time. I’ve read several tutorials about `@code_warntype` and I understand I should define types where possible, to not change them within a function, and to not mix types.

However, the MWEs do not answer my questions. I understand they are supposed to be minimal. I have tried creating a MWE, but I am not so skilled. I have some nested functions.

This is how I understand the output of `@code_warntype` - please correct me if I am wrong. My function is called `generating_pristine`.

_MethodInstance_ - this first states the type of parameters, and then the name of the parameters used in a function

_Arguments_ - these are the named parameters together with their type (coloured) used in the function  
The first line is `#self#::Core.Const(generating_pristine)` - what does this mean?

```julia
  index_vessel@_11::Int64
  index_clearance@_12::Int64
  index_extinction_parameter::Int64       
  index_callback_pristine::Vector{Float64}

```

What does `@_11` or `@_12` mean? Why are not all parameters given a number?

_Locals_ - I think these are objects within the function, that include the named parameters

```julia
 @_22::Union{Nothing, Tuple{Tuple{Int64, Any}, Tuple{Int64, Any}}}
#49::var"#49#52"
@_24::Int64
file_name_pristine::String

```

Why are some objects numbered? Do they refer to the code line or object compiled? Or the nth time a parameter is called?

_Body_ - I think this is where the calculations get done

```julia
 %94 = Base.indexed_iterate(%36, 20, @_24::Core.Const(20))::Core.PartialStruct(Tuple{Any, Int64}, Any[Any, Core.Const(21)])
           (trophic_position = Core.getfield(%94, 1))
           (@_24 = Core.getfield(%94, 2))
 %97 = Base.indexed_iterate(%36, 21, @_24::Core.Const(21))::Core.PartialStruct(Tuple{Any, Int64}, Any[Any, Core.Const(22)])
 %98 = Core.getfield(%97, 1)::Any
           Core.setfield!(num_nutrient@_94::Core.Box, :contents, %98)
           (@_24 = Core.getfield(%97, 2))

```

Is` %94` like the 94th time step while running the function? I know I need to focus on the `::Any`, but I don’t understand what part of the code or to what parameter/object it is referring to.

I have a lot of `::Any`, but I don’t understand why as I have set the type for `index_vessel` earlier, shown by `index_vessel@_11::Int64` in the Arguments.

```julia
%198 = Core.getfield(index_vessel@_100::Core.Box, :contents)::Any
│ %199 = (%198 - 1)::Any
│ %200 = (%192:%199)::Any
│ %201 = Base.getindex(%185, %200)::Any
│ %202 = Base.broadcasted(Main.:<=, %201, 0.0)::Any
│ %203 = Base.materialize(%202)::Any
│ %204 = Main.sum(%203)::Any
│ %205 = Base.convert(Main.Int64, %204)::Any
│ (extinct_pristine = Core.typeassert(%205, Main.Int64))
│ %207 = extinct_pristine::Int64
│ %208 = Core.isdefined(num_nutrient@_94::Core.Box, :contents)::Bool

```

I thought if you define a parameter, and pass it into a function, it should keep the same data and type.

I’m feeling quite lost in this. Any help is appreciated.

These are the references I have used  
[https://docs.julialang.org/en/v1/manual/performance-tips/](https://docs.julialang.org/en/v1/manual/performance-tips/)  
[https://tutorials.sciml.ai/html/introduction/03-optimizing\_diffeq\_code.html](https://tutorials.sciml.ai/html/introduction/03-optimizing_diffeq_code.html)  
[https://techytok.com/code-optimisation-in-julia/](https://techytok.com/code-optimisation-in-julia/)  
[https://book.sciml.ai/notes/02/](https://book.sciml.ai/notes/02/)  
[https://www.cs.purdue.edu/homes/hnassar/JPUG/performance.html](https://www.cs.purdue.edu/homes/hnassar/JPUG/performance.html)  
[https://m3g.github.io/JuliaNotes.jl/stable/instability/](https://m3g.github.io/JuliaNotes.jl/stable/instability/)

---

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**Author:** ![goerch](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerch/32/29122_2.png) [@goerch](https://discourse.julialang.org/u/goerch)\
**Post date:** [May 2, 2022, 10:23am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/2 "2022-05-02T10:23:24Z")

</div>

Just to be sure: did you check with a [profiler](https://docs.julialang.org/en/v1/manual/profile/) first?

---

<div class="post-metadata">

**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 10:33am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/3 "2022-05-02T10:33:21Z")

</div>

I ran `@profile` but I don’t understand how to read it either. What specifically am I looking for?  
It is quite long, but I know it shows how many allocations are needed for certain parts. Here is the first part

```julia
=========================================================
     ╎44245 @Base\client.jl:495; _start()
     ╎ 44245 @Base\client.jl:309; exec_options(opts::Base.JLOptions)
     ╎ 44245 @Base\client.jl:379; run_main_repl(interactive::Bool, quiet::Bool, banner::Bool, history_file::Bool, color_set::Bool)
     ╎ 44245 @Base\essentials.jl:714; invokelatest
     ╎ 44245 @Base\essentials.jl:716; #invokelatest#2
     ╎ 44245 @Base\client.jl:394; (::Base.var"#930#932"{Bool, Bool, Bool})(REPL::Module)
     ╎ ╎ 44245 ...package_win64\build\usr\share\julia\stdlib\v1.7\REPL\src\REPL.jl:351; run_repl(repl::REPL.AbstractREPL, consumer::Any)
     ╎ ╎ 44245 ...package_win64\build\usr\share\julia\stdlib\v1.7\REPL\src\REPL.jl:364; run_repl(repl::REPL.AbstractREPL, consumer::Any; backend_on_current_task::Bool)
     ╎ ╎ 44245 ...ackage_win64\build\usr\share\julia\stdlib\v1.7\REPL\src\REPL.jl:231; start_repl_backend(backend::REPL.REPLBackend, consumer::Any)
     ╎ ╎ 44245 ...ackage_win64\build\usr\share\julia\stdlib\v1.7\REPL\src\REPL.jl:246; repl_backend_loop(backend::REPL.REPLBackend)
     ╎ ╎ 44245 ...ackage_win64\build\usr\share\julia\stdlib\v1.7\REPL\src\REPL.jl:150; eval_user_input(ast::Any, backend::REPL.REPLBackend)
     ╎ ╎ ╎ 44245 @Base\boot.jl:373; eval
     ╎ ╎ ╎ 44245 @Atom\src\repl.jl:216; evalrepl(mod::Module, line::String)
     ╎ ╎ ╎ 44245 @Base\logging.jl:623; with_logger
     ╎ ╎ ╎ 44245 @Base\logging.jl:511; with_logstate(f::Function, logstate::Any)
     ╎ ╎ ╎ 44245 @Atom\src\repl.jl:228; (::Atom.var"#258#260"{Module})()
     ╎ ╎ ╎ ╎ 44245 @Atom\src\repl.jl:198; repleval(mod::Module, line::Expr)
     ╎ ╎ ╎ ╎ 44245 @Base\boot.jl:373; eval
     ╎ ╎ ╎ ╎ 44241 untitled-403d8f52abe991641ade3c3e069763e9:55; generating_pristine(Ropt::Float64, γ::Float64, num_nutrient::Int64, num_plant::Int64, num_a...
     ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:162; (::CommonSolve.var"#solve##kw")(::NamedTuple{(:abstol, :reltol, :callback), Tuple{Float64,...
     ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:168; #solve#40
     ╎ ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:173; solve_up##kw
     ╎ ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:182; solve_up(prob::ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Tuple{Vector{F...
     ╎ ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:142; solve_call##kw
     ╎ ╎ ╎ ╎ ╎ 44241 @DiffEqBase\src\solve.jl:155; #solve_call#39
     ╎ ╎ ╎ ╎ ╎ 44241 @Sundials\src\common_interface\solve.jl:14; __solve##kw
     ╎ ╎ ╎ ╎ ╎ ╎ 44241 @Sundials\src\common_interface\solve.jl:14; __solve##kw
     ╎ ╎ ╎ ╎ ╎ ╎ 44241 @Sundials\src\common_interface\solve.jl:14; __solve##kw
     ╎ ╎ ╎ ╎ ╎ ╎ 44241 @Sundials\src\common_interface\solve.jl:14; __solve##kw
     ╎ ╎ ╎ ╎ ╎ ╎ 44241 @Sundials\src\common_interface\solve.jl:14; __solve##kw
     ╎ ╎ ╎ ╎ ╎ ╎ 13 @Sundials\src\common_interface\solve.jl:14; __solve(prob::ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Tuple{Vecto...
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 13 @Sundials\src\common_interface\solve.jl:123; (::SciMLBase.var"#__init##kw")(::NamedTuple{(:abstol, :reltol, :callback), Tuple{Fl...
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 13 @Sundials\src\common_interface\solve.jl:400; __init(prob::ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Tuple{Vect...
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 13 @SciMLBase\src\scimlfunctions.jl:345; ODEFunction
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 4 ...Julia WD\phd-julia-code\Function running fisheries.jl:82; dBdT(dB::Vector{Float64}, bioS::Vector{Float64}, p::Tuple{Vector{Float64}, Float6...
    1╎ ╎ ╎ ╎ ╎ ╎ ╎ 1 ...Julia WD\phd-julia-code\Function running fisheries.jl:6; FF(num_nutrient::Int64, bm::Vector{Float64}, foodWeb::Matrix{Float64}, pred::Int6...
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 3 ...Julia WD\phd-julia-code\Function running fisheries.jl:11; FF(num_nutrient::Int64, bm::Vector{Float64}, foodWeb::Matrix{Float64}, pred::Int6...
    3╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 3 @Base\math.jl:907; ^
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 5 ...Julia WD\phd-julia-code\Function running fisheries.jl:107; dBdT(dB::Vector{Float64}, bioS::Vector{Float64}, p::Tuple{Vector{Float64}, Float6...        
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 5 ...Julia WD\phd-julia-code\Function running fisheries.jl:11; FF(num_nutrient::Int64, bm::Vector{Float64}, foodWeb::Matrix{Float64}, pred::Int6...
    1╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 1 @Base\float.jl:405; *
    4╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 4 @Base\math.jl:907; ^
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 4 ...Julia WD\phd-julia-code\Function running fisheries.jl:116; dBdT(dB::Vector{Float64}, bioS::Vector{Float64}, p::Tuple{Vector{Float64}, Float6...        
     ╎ ╎ ╎ ╎ ╎ ╎ ╎ 4 ...Julia WD\phd-julia-code\Function running fisheries.jl:11; FF(num_nutrient::Int64, bm::Vector{Float64}, foodWeb::Matrix{Float64}, pred::Int6...        
    4╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 4 @Base\math.jl:907; ^

```

---

<div class="post-metadata">

**Author:** ![goerch](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerch/32/29122_2.png) [@goerch](https://discourse.julialang.org/u/goerch)\
**Post date:** [May 2, 2022, 10:38am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/4 "2022-05-02T10:38:09Z")

</div>

[Here](https://discourse.julialang.org/t/speed-up-for-loop-with-multithreading/79823/10) is how I do it.

---

<div class="post-metadata">

**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 2, 2022, 10:44am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/5 "2022-05-02T10:44:50Z")

</div>

> [@HelgavonLichtenstein](#):
>
> What does `@_11` or `@_12` mean? Why are not all parameters given a number?

They are given a number when you have multiple variables with the same name. For example:

```julia
julia> f(x, y) = (x = 2; x+y)
f (generic function with 2 methods)

julia> @code_warntype f(3, 2)
MethodInstance for f(::Int64, ::Int64)
  from f(x, y) in Main at REPL[23]:1
Arguments
  #self#::Core.Const(f)
  x@_2::Int64

```

The meaning of the number itself is a bit technical but it is basically an index which is used to identify various properties about the variable.

> [@HelgavonLichtenstein](#):
>
> Is ` %94` like the 94th time step while running the function?

It is called an “SSA value”. You can read a bit about it here [Static single-assignment form - Wikipedia](https://en.wikipedia.org/wiki/Static_single_assignment_form). It is basically a variable that is only assigned to once.

> [@HelgavonLichtenstein](#):
>
> I have a lot of `::Any` , but I don’t understand why as I have set the type for `index_vessel` earlier, shown by `index_vessel@_11::Int64` in the Arguments.

Looking at ` Core.getfield(index_vessel@_100::Core.Box, :contents)` it seems you have a `Box` which can happen if you for example do something like:

```julia
julia> function f(x::Int)
           g() = x += 1
           return g()
       end
f (generic function with 3 methods)

julia> @code_warntype f(2)
MethodInstance for f(::Int64)
  from f(x::Int64) in Main at REPL[30]:1
Arguments
  #self#::Core.Const(f)
  x@_2::Int64
Locals
  g::var"#g#1"
  x@_4::Union{Int64, Core.Box}
Body::Any
1 ─ (x@_4 = x@_2)
│ (x@_4 = Core.Box(x@_4::Int64))
│ (g = %new(Main.:(var"#g#1"), x@_4::Core.Box))
│ %4 = (g)()::Any
└── return %4

```

(rebind a variable inside another function).

---

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 10:56am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/6 "2022-05-02T10:56:35Z")

</div>

This looks neat!

A lot of these bars seem big. Should I try looking at the red parts (allocating)?

 ![image](https://global.discourse-cdn.com/julialang/original/3X/8/4/84f05cae066830cbe473f5b7a5ffcbe06594fbb8.png)

---

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 11:07am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/7 "2022-05-02T11:07:50Z")

</div>

> [@kristoffer.carlsson](#):
>
> rebind a variable inside another function

For some things, I preallocate the size and pass this as an argument to create the object, for example `v`  
For others, I define it within the function. Which one is correct?

```julia
const num_nutrient = 2

function create_vectors()
    v = zeros(num_nutrient)
    v::Vector{Float64} = create_v(num_nutrient,v)
end

function create_v(num_nutrient,v)
    v[1] = 1.0
    v[2] = 0.5
    return v
end

```

Is this the correct way?

---

<div class="post-metadata">

**Author:** ![goerch](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerch/32/29122_2.png) [@goerch](https://discourse.julialang.org/u/goerch)\
**Post date:** [May 2, 2022, 12:17pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/8 "2022-05-02T12:17:48Z")

</div>

> [@HelgavonLichtenstein](#):
>
> Should I try looking at the red parts (allocating)?

I don’t see any significant allocation or dynamic dispatch in the image you posted. You can click one of the bigger bars and should then see were the time is spent in your source code or in one of the included packages.

---

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**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 2, 2022, 1:42pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/9 "2022-05-02T13:42:38Z")

</div>

> [@HelgavonLichtenstein](#):
>
> For some things, I preallocate the size and pass this as an argument to create the object, for example `v`  
> For others, I define it within the function. Which one is correct?

None of those should be related. I think it is easiest if you can show a representative piece of code that has the bad `@code_warntype` behavior.

---

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 2:48pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/10 "2022-05-02T14:48:12Z")

</div>

I agree it would be easiest to show the bad code, but I don’t know how to identify it using `@code_warntype`.

Using `Juno.profiler()` as suggested by @goerch has let me find the functions and lines of code that take a lot of time. I will assume these lines are causing the bad code messages in `@code_warntype`.

This is my attempt at a MWE. `foo3` is not what I expected, but the problematic lines are commented. I think these lines must take up a lot of resources while computing.

```julia
const num_nutrient = 2
const num_plant = 30
const index_food_web = num_nutrient+num_plant

function bigger_function(num_nutrient,num_plant,index_food_web)
    function create_vec_parameter2()
        q_one = rand(Normal(0.5,0.2))+1.0 
        bm = rand(index_food_web)
        bioS = rand(index_food_web)
        foodWeb = rand(index_food_web, index_food_web)
        b = rand(size(foodWeb))
        h = rand(size(foodWeb))
        ω = zeros(length(bm))
        return q_one,bm,bioS,foodWeb,b,h,ω
    end
    
    q_one,bm,bioS,foodWeb,b,h,ω = create_vec_parameter2()
    
    function FF2(num_nutrient, bm, foodWeb, pred, prey, b,bioS, h, ω, q_one)
        sumF = 0.0
        for k in num_nutrient+1:length(bm)
            if foodWeb[k, pred] !== 0.0
                sumF = sumF+b[k, pred]*abs(bioS[k])^q_one #this is a problem line
            end
        end
        return (((ω[pred]*b[prey, pred])^q_one)/(ω[pred]*h[pred]*sumF))/bm[pred]
    end
    
    function one_more_function(num_nutrient,num_plant,index_food_web,bioS,bm,b, h, ω, q_one)
        foo = 0.0
        for j in (num_nutrient+num_plant+1):(index_food_web)
            foo = foo + bioS[j]*FF2(num_nutrient, bm, foodWeb, pred, prey, b,bioS, h, ω, q_one) #this is a bigger problem line
        end
        return foo
    end
    
    foo2 = one_more_function(num_nutrient,num_plant,index_food_web,bioS,bm,b, h, ω, q_one)

end

foo3 = bigger_function(num_nutrient,num_plant,index_food_web)

```

---

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**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 2, 2022, 2:54pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/11 "2022-05-02T14:54:22Z")

</div>

> [@HelgavonLichtenstein](#):
>
> This is my attempt at a MWE, except I can’t get it to work. `bioS` isn’t being passed to `one_more_function` and I don’t understand why. It is probably a scoping issue I can’t see right now.

There are multiple issues with the code:

You need to assign the return values to variables, for example

- ` q_one,bm,bioS,foodWeb,b,h,ω = create_vec_parameter2()`
- `c` is not defined in the call to `one_more_function`.
- `FF2` is not called with the correct number of arguments (`bioS` seems to be missing).

---

<div class="post-metadata">

**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 3:01pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/12 "2022-05-02T15:01:40Z")

</div>

Thank you for your reply. I have edited my MWE.

---

<div class="post-metadata">

**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 2, 2022, 3:32pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/13 "2022-05-02T15:32:30Z")

</div>

`pred` is now not defined in the call to `FF2`.

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 3:43pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/14 "2022-05-02T15:43:07Z")

</div>

It does not show up as an error for me - I wonder why.

Are you doing that thing that lets you run the code line by line?

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**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 2, 2022, 3:56pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/15 "2022-05-02T15:56:40Z")

</div>

The loop range `num_nutrient+1:length(bm)` is empty so `FF2` never runs. For example, try add a print call to it and you will see it never executes.

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 2, 2022, 4:05pm UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/16 "2022-05-02T16:05:22Z")

</div>

Well, this MWE is embarrassing. I guess I’ll withdraw my post/question then.

Thank you to everyone who replied.

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**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 3, 2022, 6:40am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/17 "2022-05-03T06:40:19Z")

</div>

> [@HelgavonLichtenstein](#):
>
> Well, this MWE is embarrassing. I guess I’ll withdraw my post/question then.

Well, you don’t have to, unless everything is fixed after the missing argument. The MWE can just be fixed and then we can keep looking at it.

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [May 3, 2022, 10:04am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/18 "2022-05-03T10:04:13Z")

</div>

I realised I needed a double loop in `one_more_function()`, but `FF2` still does not run. I don’t know what to do.

```julia
const num_nutrient = 2
const num_plant = 30
const index_food_web = num_nutrient+num_plant

function bigger_function(num_nutrient,num_plant,index_food_web)
    function create_vec_parameter2()
        q_one = rand(Normal(0.5,0.2))+1.0 
        bm = rand(index_food_web)
        bioS = rand(index_food_web)
        foodWeb = rand(index_food_web, index_food_web)
        b = rand(size(foodWeb))
        h = rand(size(foodWeb))
        ω = zeros(length(bm))
        return q_one,bm,bioS,foodWeb,b,h,ω
    end
    
    q_one,bm,bioS,foodWeb,b,h,ω = create_vec_parameter2()
    
    function FF2(num_nutrient, bm, foodWeb, pred, prey, b,bioS, h, ω, q_one)
        sumF = 0.0
        for k in num_nutrient+1:length(bm)
            if foodWeb[k, pred] !== 0.0
                sumF = sumF+b[k, pred]*abs(bioS[k])^q_one #this is a problem line
            end
        end
        return (((ω[pred]*b[prey, pred])^q_one)/(ω[pred]*h[pred]*sumF))/bm[pred]
    end
    
    function one_more_function(num_nutrient,num_plant,index_food_web,bioS,bm,b, h, ω, q_one)
        foo = 0.0
        for i in (num_nutrient+num_plant+1):(index_food_web), j in (num_nutrient+num_plant+1):(index_food_web)
            foo = foo + bioS[j]*FF2(num_nutrient, bm, foodWeb, pred, prey, b,bioS, h, ω, q_one) #this is a bigger problem line
        end
        return foo
    end
    
    foo2 = one_more_function(num_nutrient,num_plant,index_food_web,bioS,bm,b, h, ω, q_one)

end

foo3 = bigger_function(num_nutrient,num_plant,index_food_web)

```

---

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**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 3, 2022, 10:22am UTC](https://discourse.julialang.org/t/what-does-mean-in-code-warntype-and-other-questions/80360/19 "2022-05-03T10:22:03Z")

</div>

You have

```julia
const index_food_web = num_nutrient+num_plant

```

so

```julia
(num_nutrient+num_plant+1):(index_food_web)

```

is equal to

```julia
(num_nutrient+num_plant+1):(num_nutrient+num_plant)

```

which in this case is `33:32` which is an empty range. What you should do is hard to say. What do you actually want to loop over?