# Julia 1.11.1 gives different results from 1.10.5
**URL:** https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433
**Category:** General Usage
**Created:** [December 4, 2024, 2:34am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433 "2024-12-04T02:34:39Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 2:34am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/1 "2024-12-04T02:34:40Z")
I fear I have to start debugging. But: perhaps someone has had this experience already and there is a fix?
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### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [December 4, 2024, 2:36am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/2 "2024-12-04T02:36:49Z")
Does 1.11.2 fix it?
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### Author:  [@adienes](https://discourse.julialang.org/u/adienes)
#### Post date: [December 4, 2024, 2:49am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/3 "2024-12-04T02:49:11Z")
any hints at all as to where the difference might lie? what kind of code is it?
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 2:54am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/4 "2024-12-04T02:54:18Z")
'fraid not.
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### Author:  [@Dan](https://discourse.julialang.org/u/Dan)
#### Post date: [December 4, 2024, 2:57am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/5 "2024-12-04T02:57:21Z")
Perhaps 1.11.1 fixed some incorrect stuff which revealed something to fix in your code. This can be a blessing in disguise.
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### Author:  [@mbauman](https://discourse.julialang.org/u/mbauman)
#### Post date: [December 4, 2024, 3:29am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/6 "2024-12-04T03:29:18Z")
I’ve seen numerical values change on upgrades, but it’s always tracked back to either `@simd` (or fastmath and the like) or the RNG or changes in packages that simultaneously upgraded.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 3:33am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/7 "2024-12-04T03:33:46Z")
No clue where or what. The first four tests run fine, the last one is broken. ([pace.jl](https://github.com/PetrKryslUCSD/FinEtoolsDDMethods.jl/blob/main/examples/conc/pace.jl) – sequential, the same problem for the MPI implementation in [pace\_mpi.jl](https://github.com/PetrKryslUCSD/FinEtoolsDDMethods.jl/blob/main/examples/conc/pace_mpi.jl)): the iteration stagnates. All works fine with 1.10.5.
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### Author:  [@gdalle](https://discourse.julialang.org/u/gdalle)
#### Post date: [December 4, 2024, 4:35am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/8 "2024-12-04T04:35:18Z")
Can you provide a minimum working example?
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### Author:  [@abraemer](https://discourse.julialang.org/u/abraemer)
#### Post date: [December 4, 2024, 7:05am UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/9 "2024-12-04T07:05:14Z")
So you are only checking the number of iterations some solver takes in these scripts, right? And these changed? Did you also compare the solutions and do they differ? If not then it might not be a “correctness” bug after all.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 1:42pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/10 "2024-12-04T13:42:11Z")
If I could, I would have found the error by now.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 2:40pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/11 "2024-12-04T14:40:26Z")
I do check that the solution is correct, not only that the residual drops down to zero. But not in the scripts used in timing runs.
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### Author:  [@gdalle](https://discourse.julialang.org/u/gdalle)
#### Post date: [December 4, 2024, 3:18pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/12 "2024-12-04T15:18:18Z")
> [@PetrKryslUCSD](#):
>
> If I could, I would have found the error by now.
Without a reasonably small example, I’m not sure someone else will be able to find the problem in your stead.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 3:19pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/13 "2024-12-04T15:19:51Z")
I thought it was clear that I was not looking for someone to “find the error in my stead”?
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### Author:  [@world-peace](https://discourse.julialang.org/u/world-peace)
#### Post date: [December 4, 2024, 4:14pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/14 "2024-12-04T16:14:39Z")
What has changed?
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 4:15pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/15 "2024-12-04T16:15:38Z")
??? Not sure I follow…
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### Author:  [@world-peace](https://discourse.julialang.org/u/world-peace)
#### Post date: [December 4, 2024, 4:19pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/16 "2024-12-04T16:19:07Z")
Am I missing something?
The title of this post says 1.11 has broken the correctness (presumably semantic correctness) of your code.
But no details were provided.
> [@PetrKryslUCSD](#):
>
> I fear I have to start debugging
Without debugging it is difficult to envision how you will find a solution.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 4:24pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/17 "2024-12-04T16:24:02Z")
Amen.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [December 4, 2024, 5:16pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/18 "2024-12-04T17:16:44Z")
Just in case you’re interested, I found the first difference:
Two arrays are computed with different bits.
Julia 1.10.5:
```julia
fens.xyz[nl, :] = [10.0 1.0 0.2857142857142857; 10.0 1.0 0.42857142857142855; 10.0 1.0 0.5714285714285714; 10.0 1.0 0.7142857142857143; 10.0 1.0 0.8571428571428571; 10.0 1.0 1.0]
```
Julia 1.11.2:
```julia
fens.xyz[nl, :] = [10.0 1.0 0.2857142857142857; 9.999999999999998 1.0 0.42857142857142855; 10.0 1.0 0.5714285714285714; 10.0 1.0 0.7142857142857143; 10.0 1.0 0.8571428571428571; 10.0 1.0 1.0]
```
This, in combination with a typo that eliminated the use of a non-zero tolerance, produced diverging results.
What changed so that Julia does not produce bit identical patterns?
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### Author:  [@mbauman](https://discourse.julialang.org/u/mbauman)
#### Post date: [December 4, 2024, 5:31pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/19 "2024-12-04T17:31:03Z")
> [@PetrKryslUCSD](#):
>
> What changed so that Julia does not produce bit identical patterns?
It’s still hard to say — see my list above. It’s likely to be some arithmetic or BLAS routine that internally allows for re-association and doesn’t guarantee perfectly rounded results for all inputs. Or it’s code you wrote that allows for the same.
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### Author:  [@adienes](https://discourse.julialang.org/u/adienes)
#### Post date: [December 4, 2024, 5:58pm UTC](https://discourse.julialang.org/t/julia-1-11-1-gives-different-results-from-1-10-5/123433/20 "2024-12-04T17:58:22Z")
could it possibly be related to [10.0^68 gives a different result on nightly vs 1.11 after llvm-muladd pass removal · Issue #56312 · JuliaLang/julia · GitHub](https://github.com/JuliaLang/julia/issues/56312) ? I’m not sure what would have changed in this regard from 1.11 to 1.11.1 though
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