# Hwloc.jl num\_physical\_cores()

**URL:** <https://discourse.julialang.org/t/hwloc-jl-num-physical-cores/5626>\
**Category:** General Usage\
**Created:** [August 30, 2017, 8:32am UTC](https://discourse.julialang.org/t/hwloc-jl-num-physical-cores/5626 "2017-08-30T08:32:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![usefulhyun](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/usefulhyun/32/1770_2.png) [@usefulhyun](https://discourse.julialang.org/u/usefulhyun)\
**Post date:** [August 30, 2017, 8:32am UTC](https://discourse.julialang.org/t/hwloc-jl-num-physical-cores/5626/1 "2017-08-30T08:32:39Z")

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I am using Julia 0.6.0.

I have added Package Hwloc and imported Hwloc packages.  
And I’d like to call a function “num\_physical\_cores()”  
But this function does not exist.  
How do I do use this function?

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<div class="post-metadata">

**Author:** ![greg\_plowman](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/greg_plowman/32/8100_2.png) [@greg\_plowman](https://discourse.julialang.org/u/greg_plowman)\
**Post date:** [August 30, 2017, 9:15am UTC](https://discourse.julialang.org/t/hwloc-jl-num-physical-cores/5626/2 "2017-08-30T09:15:04Z")

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This function seems a recent addition, and isn’t in the latest tagged release.

Until a new version is tagged, you could checkout the master version: `Pkg.checkout("Hwloc")`

Alternatively, follow the example in documentation:

```julia
topology = Hwloc.topology_load()
counts = Hwloc.histmap(topology)
ncores = counts[:Core]

```

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<div class="post-metadata">

**Author:** ![usefulhyun](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/usefulhyun/32/1770_2.png) [@usefulhyun](https://discourse.julialang.org/u/usefulhyun)\
**Post date:** [August 30, 2017, 9:59am UTC](https://discourse.julialang.org/t/hwloc-jl-num-physical-cores/5626/3 "2017-08-30T09:59:42Z")

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I really appreciate your answering.  
I solved the problem by `Pkg.checkout("Hwloc")` command.  
Thank you.