# \#runtime-dispatch

**URL:** https://discourse.julialang.org/tag/runtime-dispatch/1579.md

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## [Static call at runtime](https://discourse.julialang.org/t/static-call-at-runtime/134516)

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**Author:** [@epilliat](https://discourse.julialang.org/u/epilliat)\
**Replies:** 7\
**Last updated:** [December 14, 2025, 9:55am UTC](https://discourse.julialang.org/t/static-call-at-runtime/134516 "2025-12-14T09:55:56Z")

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This problem comes from several pieces of code I’ve been struggling to optimize due to missunderstanding of Julia compiler. I would like to know if there are any “standard” way to do this. Consider a function f that doe…

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## [Performance discrepancy for different ways of piping/composing functions for handling runtime dispatch](https://discourse.julialang.org/t/performance-discrepancy-for-different-ways-of-piping-composing-functions-for-handling-runtime-dispatch/129773)

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**Author:** [@frankwswang](https://discourse.julialang.org/u/frankwswang)\
**Replies:** 9\
**Last updated:** [June 13, 2025, 4:30am UTC](https://discourse.julialang.org/t/performance-discrepancy-for-different-ways-of-piping-composing-functions-for-handling-runtime-dispatch/129773 "2025-06-13T04:30:29Z")

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MWE (tested on Julia 1.11.5): julia\> foo1(::Val{N}) where {N} = N foo1 (generic function with 1 method) julia\> foo2(n::Int) = Val(n) foo2 (generic function with 1 method) julia\> a = Val.(rand(Int, 1000)); julia\> usin…

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## [Why does runtime dispatch allocate when the return type is inferred?](https://discourse.julialang.org/t/why-does-runtime-dispatch-allocate-when-the-return-type-is-inferred/129061)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 5\
**Last updated:** [May 17, 2025, 2:00am UTC](https://discourse.julialang.org/t/why-does-runtime-dispatch-allocate-when-the-return-type-is-inferred/129061 "2025-05-17T02:00:25Z")

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The usual explanation for why runtime dispatches allocate is that falling back to inferring ::Any for the return type requires boxing the instance at runtime. Thing is, there seems to be a workaround. If the compiler kno…

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## [Type-instability, runtime dispatch, and heap allocations](https://discourse.julialang.org/t/type-instability-runtime-dispatch-and-heap-allocations/127985)

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**Author:** [@StevenWhitaker](https://discourse.julialang.org/u/StevenWhitaker)\
**Replies:** 3\
**Last updated:** [April 12, 2025, 5:51am UTC](https://discourse.julialang.org/t/type-instability-runtime-dispatch-and-heap-allocations/127985 "2025-04-12T05:51:45Z")

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I wanted to check/improve my understanding of allocations caused by type-instabilities. Consider the following: function f() x = g() y = h(x) z = b(x) end g() = Any\[1\]\[1\] h(::Int) = 1 h(::Any) = Any\[2\]\[1\]…

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## [Avoiding allocations and run-time dispatch with ForwardDiff](https://discourse.julialang.org/t/avoiding-allocations-and-run-time-dispatch-with-forwarddiff/123699)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 2\
**Last updated:** [December 11, 2024, 1:29pm UTC](https://discourse.julialang.org/t/avoiding-allocations-and-run-time-dispatch-with-forwarddiff/123699 "2024-12-11T13:29:24Z")

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I have an optimization problem which involves solving an ODE and finding the input to the “system” such that an objective is minimized. A MWE of a toy problem is below: import Optimization import ForwardDiff import Opti…

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## [Runtime dispatch in struct that contains struct](https://discourse.julialang.org/t/runtime-dispatch-in-struct-that-contains-struct/118840)

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**Author:** [@JADekker](https://discourse.julialang.org/u/JADekker)\
**Replies:** 5\
**Last updated:** [August 31, 2024, 2:33pm UTC](https://discourse.julialang.org/t/runtime-dispatch-in-struct-that-contains-struct/118840 "2024-08-31T14:33:34Z")

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Hi, in my code, I have a structure similar to the below. The function that I call in running should be determined by FooContainer.foo, so it is clear to me that I have runtime dispatch here. What is the idiomatic way to …

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## [The Problem with Julia that makes me want to leave - First run Times](https://discourse.julialang.org/t/the-problem-with-julia-that-makes-me-want-to-leave-first-run-times/114316)

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**Author:** [@Maddy](https://discourse.julialang.org/u/Maddy)\
**Replies:** 52\
**Last updated:** [May 18, 2024, 6:05pm UTC](https://discourse.julialang.org/t/the-problem-with-julia-that-makes-me-want-to-leave-first-run-times/114316 "2024-05-18T18:05:01Z")

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I started my programming journey in Python. A year ago, to create a real-time simulation, I came to know about Julia with its great speed. I used Julia for the first time and I remember the spark of joy I had while mess…

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## [Elimination of (unnecessary) runtime dispatch allocations](https://discourse.julialang.org/t/elimination-of-unnecessary-runtime-dispatch-allocations/113475)

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**Author:** [@nielsls](https://discourse.julialang.org/u/nielsls)\
**Replies:** 13\
**Last updated:** [May 5, 2024, 12:00pm UTC](https://discourse.julialang.org/t/elimination-of-unnecessary-runtime-dispatch-allocations/113475 "2024-05-05T12:00:26Z")

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Avoiding runtime dispatch is perhaps the #1 optimization advice in Julia forums. As I understand it, the reason is that when the Julia compiler does a runtime dispatch it does not at compile-time neccesarily know the re…