# Julia faster than C++ on a converted large simulation model

**URL:** <https://discourse.julialang.org/t/julia-faster-than-c-on-a-converted-large-simulation-model/139787>\
**Category:** General Usage\
**Created:** [October 2, 2026, 10:18am UTC](https://discourse.julialang.org/t/julia-faster-than-c-on-a-converted-large-simulation-model/139787 "2026-10-02T10:18:00Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [October 3, 2026, 9:28am UTC](https://discourse.julialang.org/t/julia-faster-than-c-on-a-converted-large-simulation-model/139787/13 "2026-10-03T09:28:26Z")

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> [@Palli](#):
>
> Can you say which Claude? Like Claude Code presumably, and Opus 5.5 and/or Fable 5.1? I’m not sure you can use Claude code with two models at the same time as with EvoX (or Devin Fusion). Do you know cost or tokens spent?

It’s about 12k LOC (comments, libraries code and doc removed)  
I am using Claude Opus 5.5, don’t know how to measure the cost/tokens usage of a particular task. I am using the “pro” account provided by my university, not API key.

To respond to other comments, I am not selling anything here, nor looking for clicks, just reported my experience as someone working on scientific simulations from a thematic domain. You need a spatial model, you see Python is too slow, you learn and implement your model in C++, and see it works “sufficiently fast” and you are happy.  
I wasn’t able to squeeze C++ performance the way it could have been possible. I am sure the LLM could do it, but I am not sure I could then read the code. My claim is that doing that in Julia (by myself or by the LLM) is much easier while keeping the code high-level, compact, and readable by a non-expert. At least, this has been my experience.

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