# Histogram fit error

**URL:** <https://discourse.julialang.org/t/histogram-fit-error/6900>\
**Category:** Statistics\
**Tags:** error\
**Created:** [November 5, 2017, 9:30pm UTC](https://discourse.julialang.org/t/histogram-fit-error/6900 "2017-11-05T21:30:29Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![SebastianM-C](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sebastianm-c/32/2480_2.png) [@SebastianM-C](https://discourse.julialang.org/u/SebastianM-C)\
**Post date:** [November 5, 2017, 9:30pm UTC](https://discourse.julialang.org/t/histogram-fit-error/6900/1 "2017-11-05T21:30:29Z")

</div>

Hello,  
I sometimes get an `InexactError()` when using `fit(Histogram, data, ws, 0:0.25:4, closed=:left)`.  
The issue is very strange because it doesn’t always happen. The same code sometimes runs fine, but sometimes  
I get the following error:

```julia
ERROR: LoadError: InexactError()
Stacktrace:
 [1] trunc(::Type{Int64}, ::Float64) at ./float.jl:672
 [2] searchsortedlast(::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}, ::Float64, ::Base.Order.ForwardOrdering) at ./sort.jl:157
 [3] _edge_binindex at /home/user/.julia/v0.6/StatsBase/src/hist.jl:183 [inlined]
 [4] (::StatsBase.##80#81{StatsBase.Histogram{Float64,1,Tuple{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}}}})(::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}, ::Float64) at /home/user/.julia/v0.6/StatsBase/src/hist.jl:177
 [5] push!(::StatsBase.Histogram{Float64,1,Tuple{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}}}, ::Tuple{Float64}, ::Float64) at /home/user/.julia/v0.6/StatsBase/src/hist.jl:247
 [6] append!(::StatsBase.Histogram{Float64,1,Tuple{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}}}, ::Tuple{Array{Float64,1}}, ::Array{Float64,1}) at /home/user/.julia/v0.6/StatsBase/src/hist.jl:267
 [7] #fit#93(::Symbol, ::Function, ::Type{StatsBase.Histogram{Float64,N,E} where E where N}, ::Tuple{Array{Float64,1}}, ::StatsBase.Weights{Float64,Float64,Array{Float64,1}}, ::Tuple{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}}) at /home/user/.julia/v0.6/StatsBase/src/hist.jl:289
 [8] (::StatsBase.#kw##fit)(::Array{Any,1}, ::StatsBase.#fit, ::Type{StatsBase.Histogram{Float64,N,E} where E where N}, ::Tuple{Array{Float64,1}}, ::StatsBase.Weights{Float64,Float64,Array{Float64,1}}, ::Tuple{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}}) at ./<missing>:0 (repeats 2 times)
 [9] #fit#88(::Array{Any,1}, ::Function, ::Type{StatsBase.Histogram}, ::Array{Float64,1}, ::StatsBase.Weights{Float64,Float64,Array{Float64,1}}, ::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}, ::Vararg{StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}},N} where N) at /home/user/.julia/v0.6/StatsBase/src/hist.jl:233
 [10] (::StatsBase.#kw##fit)(::Array{Any,1}, ::StatsBase.#fit, ::Type{StatsBase.Histogram}, ::Array{Float64,1}, ::StatsBase.Weights{Float64,Float64,Array{Float64,1}}, ::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}) at ./<missing>:0
 [11] include_from_node1(::String) at ./loading.jl:576
 [12] include(::String) at ./sysimg.jl:14
 [13] process_options(::Base.JLOptions) at ./client.jl:305
 [14] _start() at ./client.jl:371
while loading /home/user/.problems/histogram.jl, in expression starting on line 730

```

I tried to reproduce the error with some simple data, but I was not successful. I am not sure if the problem is related to the data, or I was not lucky.  
I created a gist with some data which **sometimes** reproduces the error: [https://gist.github.com/SebastianM-C/06b66daa66d05fde19538fc4b1f07b25](https://gist.github.com/SebastianM-C/06b66daa66d05fde19538fc4b1f07b25)

My `versioninfo()` is:

```julia
julia> versioninfo()
Julia Version 0.6.1
Commit 0d7248e2ff (2017-10-24 22:15 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i7-4720HQ CPU @ 2.60GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.9.1 (ORCJIT, haswell)

```

I have StatsBase version 0.19.0:

```julia
julia> Pkg.status("StatsBase")
 - StatsBase 0.19.0

```

Am I missing something?

---

<div class="post-metadata">

**Author:** ![mkborregaard](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mkborregaard/32/556_2.png) [@mkborregaard](https://discourse.julialang.org/u/mkborregaard)\
**Post date:** [November 6, 2017, 8:40am UTC](https://discourse.julialang.org/t/histogram-fit-error/6900/2 "2017-11-06T08:40:46Z")

</div>

I can’t reproduce using your gist (on 0.6.1).

---

<div class="post-metadata">

**Author:** ![nalimilan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nalimilan/32/147_2.png) [@nalimilan](https://discourse.julialang.org/u/nalimilan)\
**Post date:** [November 6, 2017, 9:00am UTC](https://discourse.julialang.org/t/histogram-fit-error/6900/3 "2017-11-06T09:00:00Z")

</div>

Actually I can reproduce it from time to time on Julia 0.6 and 0.7. Thanks for posting a MWE, that’s very useful!

The `InexactError` is due to the presence of a `NaN`, which appears in `append!` when calling `_multi_getindex` with the index `716`. Looks like this is due to the fact that the weights vector contains 716 elements, but the data only contains 715 elements. Due to `@inbounds`, depending on the memory layout, the result can either contain a (semi-random) valid float value, or an invalid one. So in all cases something is wrong, and it can affect the result.

Could you file an issue against StatsBase? We should ensure the array sizes are compatible. Maybe Julia itself should do that with `eachindex`, which would have caught the problem (I’ve filed [an issue](https://github.com/JuliaLang/julia/issues/24486)).

---

<div class="post-metadata">

**Author:** ![SebastianM-C](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sebastianm-c/32/2480_2.png) [@SebastianM-C](https://discourse.julialang.org/u/SebastianM-C)\
**Post date:** [November 6, 2017, 1:34pm UTC](https://discourse.julialang.org/t/histogram-fit-error/6900/4 "2017-11-06T13:34:58Z")

</div>

Thank you very much! I opened an issue: [https://github.com/JuliaStats/StatsBase.jl/issues/315](https://github.com/JuliaStats/StatsBase.jl/issues/315)