# The difference between PCHIPInterpolation and SimplePCHIP

**URL:** <https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927>\
**Category:** General Usage\
**Tags:** package\
**Created:** [October 17, 2021, 11:41am UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927 "2021-10-17T11:41:48Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![leon](https://avatars.discourse-cdn.com/v4/letter/l/dc4da7/32.png) [@leon](https://discourse.julialang.org/u/leon)\
**Post date:** [October 17, 2021, 11:41am UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927/1 "2021-10-17T11:41:48Z")

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Anyone knows their differences? I wonder which one I should use?

Thanks.

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**Author:** ![Palli](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/palli/32/3380_2.png) [@Palli](https://discourse.julialang.org/u/Palli)\
**Post date:** [October 17, 2021, 8:04pm UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927/2 "2021-10-17T20:04:06Z")

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If you look at “PCHIPInterpolation.jl” you’ll see “fork from” SimplePCHIP, i.e. the code is the same, just updated, so I wouldn’t worry about the latter, unmaintained package, it seems. I used that package at some point, and it actually works, so both should, but I ended up using SciPy, i.e. calling from Julia to Python (because I needed also extrapolation, or thought I needed, turned out I didn’t in the end). Extrapolation hasn’t been added, in case you need that, and if I recall the Julia package wasn’t as optimized, but it was fast enough for me, not really the speed-critical part. See here:

[https://github.com/gerlero/PCHIPInterpolation.jl/pull/1](https://github.com/gerlero/PCHIPInterpolation.jl/pull/1)

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**Author:** ![leon](https://avatars.discourse-cdn.com/v4/letter/l/dc4da7/32.png) [@leon](https://discourse.julialang.org/u/leon)\
**Post date:** [October 17, 2021, 8:50pm UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927/3 "2021-10-17T20:50:10Z")

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Many thanks for sharing the information! Glad to know they are the same. I will use PCHIPInterpolation.jl then.

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**Author:** ![goerch](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerch/32/29122_2.png) [@goerch](https://discourse.julialang.org/u/goerch)\
**Post date:** [October 17, 2021, 8:53pm UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927/4 "2021-10-17T20:53:56Z")

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Why not mark it as solved by Palli then?

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**Author:** ![leon](https://avatars.discourse-cdn.com/v4/letter/l/dc4da7/32.png) [@leon](https://discourse.julialang.org/u/leon)\
**Post date:** [October 17, 2021, 8:57pm UTC](https://discourse.julialang.org/t/the-difference-between-pchipinterpolation-and-simplepchip/69927/5 "2021-10-17T20:57:03Z")

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My apologies. I wasn’t aware of the “resolved” function. How could I do that? Should I just click the Solution checkbox? Thanks.