# Optim.jl and runtime dispatch detected errors
**URL:** https://discourse.julialang.org/t/optim-jl-and-runtime-dispatch-detected-errors/125981
**Category:** Optimization (Mathematical)
**Created:** [February 17, 2025, 10:54am UTC](https://discourse.julialang.org/t/optim-jl-and-runtime-dispatch-detected-errors/125981 "2025-02-17T10:54:38Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Miroboru](https://discourse.julialang.org/u/Miroboru)
#### Post date: [February 17, 2025, 10:54am UTC](https://discourse.julialang.org/t/optim-jl-and-runtime-dispatch-detected-errors/125981/1 "2025-02-17T10:54:38Z")
I have a piece of simulation software that makes millions of calls to Optim.optimize during runs. I seemingly have a lot of allocations, so I use JET and tested my code with @report\_opt. The result was a large number of “runtime dispatch detected errors”. To verify that everything was ok I then ran the small toy problem from the Optim.jl tutorial:
```julia
using JET
using Optim
f(x) = (1.0 - x[1])^2 + 100.0 * (x[2] - x[1]^2)^2
x0 = [0.0, 0.0]
@report_opt optimize(f, x0)
```
The result is 71 possible errors found. Is this to be expected, or are there optimizations I am not aware of?
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [February 17, 2025, 6:36pm UTC](https://discourse.julialang.org/t/optim-jl-and-runtime-dispatch-detected-errors/125981/2 "2025-02-17T18:36:23Z")
Runtime dispatch is expected with Optim.
If you make a post with your real problem, people may have suggestions for how to improve it, or reduce the number of allocations.