# \#splines

**URL:** https://discourse.julialang.org/tag/splines/789.md

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## [Monotonic smoothing of noisy data](https://discourse.julialang.org/t/monotonic-smoothing-of-noisy-data/93184)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 21\
**Last updated:** [May 17, 2025, 3:47pm UTC](https://discourse.julialang.org/t/monotonic-smoothing-of-noisy-data/93184 "2025-05-17T15:47:46Z")

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Is there a package in Julia, or a simple algorithm, to perform monotonic smoothing of noisy data? See this Python example. NB: it is assumed that we do not know of any monotonic function or model that could fit the da…

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## [Arc length for a spline](https://discourse.julialang.org/t/arc-length-for-a-spline/36161)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 27\
**Last updated:** [February 7, 2025, 8:04am UTC](https://discourse.julialang.org/t/arc-length-for-a-spline/36161 "2025-02-07T08:04:11Z")

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Given some spline (e.g. Dierckx.jl, Interpolations.jl), is there a good way to get its arc length? Right now I’m using this: using LinearAlgebra, Dierckx t = range(0, stop = π, length = 100) x = cos.(t) y = sin.(t) spl…

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## [\[pre-ANN\] SplineGrids.jl - Efficient evaluation of spline/NURBS geometries of any dimensionality](https://discourse.julialang.org/t/pre-ann-splinegrids-jl-efficient-evaluation-of-spline-nurbs-geometries-of-any-dimensionality/124459)

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**Author:** [@BdeKoning](https://discourse.julialang.org/u/BdeKoning)\
**Replies:** 3\
**Last updated:** [January 15, 2025, 5:41am UTC](https://discourse.julialang.org/t/pre-ann-splinegrids-jl-efficient-evaluation-of-spline-nurbs-geometries-of-any-dimensionality/124459 "2025-01-15T05:41:13Z")

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Hello everyone, I’d like to announce a package I’ve been working on as a passion project for the past few weeks: SplineGrids.jl: Repo: SouthEndMusic/SplineGrids.jl: Evaluating splines of arbitrary dimensionality on a …

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## [Cubic spline for non monotonic vector](https://discourse.julialang.org/t/cubic-spline-for-non-monotonic-vector/112599)

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**Author:** [@jgr](https://discourse.julialang.org/u/jgr)\
**Replies:** 5\
**Last updated:** [April 6, 2024, 7:48pm UTC](https://discourse.julialang.org/t/cubic-spline-for-non-monotonic-vector/112599 "2024-04-06T19:48:59Z")

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I am using Spline1D from Dierckx package, and my code is Ev = \[2, 1, 3,4\] sgrid = \[0, 1, 2,4\] spl = Spline1D(Ev,sgrid) The error I got is Error on entry, no approximation returned. The following conditions must hold: …

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## [KernelAbstractions for splines](https://discourse.julialang.org/t/kernelabstractions-for-splines/104312)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 6\
**Last updated:** [March 22, 2024, 2:58pm UTC](https://discourse.julialang.org/t/kernelabstractions-for-splines/104312 "2024-03-22T14:58:48Z")

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I’m trying to code a simple b-spline (and then NURBS) on the GPU using kernels to speed up a ton of simultaneous evaluations. I’m having trouble because Cox-deBoor is recursive and throws an error when I try to use this…

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## [2D Interpolation on an irregular grid](https://discourse.julialang.org/t/2d-interpolation-on-an-irregular-grid/105247)

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**Author:** [@k\_j](https://discourse.julialang.org/u/k_j)\
**Replies:** 8\
**Last updated:** [October 20, 2023, 10:53pm UTC](https://discourse.julialang.org/t/2d-interpolation-on-an-irregular-grid/105247 "2023-10-20T22:53:52Z")

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I want to do 2D interpolation on an irregular grid. In particular, I have a function f:\\mathbb R^2 \\rightarrow \\mathbb R, (x, y) \\mapsto z. I have an irregular grid D = (x\_i, y\_i)\_i as well as the corresponding values F…

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## [Smoothing spline fit through a set of (x,y) points](https://discourse.julialang.org/t/smoothing-spline-fit-through-a-set-of-x-y-points/104873)

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**Author:** [@hanshinlee77](https://discourse.julialang.org/u/hanshinlee77)\
**Replies:** 7\
**Last updated:** [October 18, 2023, 3:09pm UTC](https://discourse.julialang.org/t/smoothing-spline-fit-through-a-set-of-x-y-points/104873 "2023-10-18T15:09:38Z")

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Hello, I have a set of (x,y) points (shown in the attached dpng) which I would like to create a smoothing spline through. Normally, I don’t have a problem doing a fit like this using Spline1D() from Dierckx.jl or inte…

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## [Monotone cubic spline interpolation on an irregular grid](https://discourse.julialang.org/t/monotone-cubic-spline-interpolation-on-an-irregular-grid/97977)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 2\
**Last updated:** [April 27, 2023, 10:45am UTC](https://discourse.julialang.org/t/monotone-cubic-spline-interpolation-on-an-irregular-grid/97977 "2023-04-27T10:45:49Z")

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Is there a package in Julia for interpolation using a monotone cubic spline interpolation on an irregular grid? I seem to be failing to find one. Interpolations.jl does provide monotone option, but only on a regular gri…

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## [Dierckx to perform a derivative over a 2d spline](https://discourse.julialang.org/t/dierckx-to-perform-a-derivative-over-a-2d-spline/96101)

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**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 8\
**Last updated:** [March 20, 2023, 11:24am UTC](https://discourse.julialang.org/t/dierckx-to-perform-a-derivative-over-a-2d-spline/96101 "2023-03-20T11:24:08Z")

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I cannot use Dierckx.jl to perform a derivative over a 2d spline even though from the documentation it seems like it should work. The help of the function derivative gives: Dierckx.derivative is a Function. # 10 metho…

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## [BasicBSpline.jl - Basic mathematical operations for B-spline](https://discourse.julialang.org/t/basicbspline-jl-basic-mathematical-operations-for-b-spline/96323)

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**Author:** [@hyrodium](https://discourse.julialang.org/u/hyrodium)\
**Replies:** 0\
**Last updated:** [March 20, 2023, 12:56am UTC](https://discourse.julialang.org/t/basicbspline-jl-basic-mathematical-operations-for-b-spline/96323 "2023-03-20T00:56:11Z")

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Hi all, I’m pleased to announce my package BasicBSpline.jl v0.9.4 (repo, docs). Introduction This package provides basic mathematical operations for B-spline. B-spline basis function Some operations for knot vector S…

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## [Add missing points in a 2D line](https://discourse.julialang.org/t/add-missing-points-in-a-2d-line/94211)

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**Author:** [@Benjamin\_Steinvorth](https://discourse.julialang.org/u/Benjamin_Steinvorth)\
**Replies:** 5\
**Last updated:** [February 7, 2023, 3:18pm UTC](https://discourse.julialang.org/t/add-missing-points-in-a-2d-line/94211 "2023-02-07T15:18:33Z")

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have some 2D data in Julia representing a circular feature with some “holes” in it. I like to interpolate these holes by finding points fitting on a curve representing the shape of the feature. Using Julia’s PlotlyJS li…

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## [Mathematica BSplineCurve in Julia](https://discourse.julialang.org/t/mathematica-bsplinecurve-in-julia/78107)

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**Author:** [@arnief3](https://discourse.julialang.org/u/arnief3)\
**Replies:** 17\
**Last updated:** [January 9, 2023, 9:05am UTC](https://discourse.julialang.org/t/mathematica-bsplinecurve-in-julia/78107 "2023-01-09T09:05:00Z")

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I am trying to achieve the same result as BSplineCurve—Wolfram Language Documentation in julia. I have used Dierckx.jl for more straightforward spline fitting but am stumped on how to place data points and knots to achie…

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## [Difference between two interpolation packages when evaluating derivatives: Interpolations.jl and Dierckx.jl](https://discourse.julialang.org/t/difference-between-two-interpolation-packages-when-evaluating-derivatives-interpolations-jl-and-dierckx-jl/61747)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 5\
**Last updated:** [December 9, 2022, 9:16pm UTC](https://discourse.julialang.org/t/difference-between-two-interpolation-packages-when-evaluating-derivatives-interpolations-jl-and-dierckx-jl/61747 "2022-12-09T21:16:12Z")

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Recently I had a chance to test two interpolation packages, Interpolations.jl and Dierckx.jl. I found a difference between the two packages in the way they treat the boundary points when evaluating derivatives. I think…

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## [Clamped Cubic Spline](https://discourse.julialang.org/t/clamped-cubic-spline/90222)

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**Author:** [@JHall](https://discourse.julialang.org/u/JHall)\
**Replies:** 4\
**Last updated:** [November 29, 2022, 4:43pm UTC](https://discourse.julialang.org/t/clamped-cubic-spline/90222 "2022-11-29T16:43:14Z")

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Hi all, I am trying to use cubic spline interpolation where I specify the derivatives at the endpoint. The functions I am trying to interpolate with are value functions and thus often have poles at 0. As a consequence…

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## [\`Plots.jl\` spline](https://discourse.julialang.org/t/plots-jl-spline/88720)

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**Author:** [@this\_josh](https://discourse.julialang.org/u/this_josh)\
**Replies:** 8\
**Last updated:** [October 21, 2022, 11:30am UTC](https://discourse.julialang.org/t/plots-jl-spline/88720 "2022-10-21T11:30:26Z")

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How can I plot a line with line\_style=spline in Plots.jl? For an example of what I’m after see the ‘spline’ trace in these plotly docs The closest I can find in the docs is about how to step Any suggestions should be a…

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## [Derivatives of B-Spline w.r.t their degrees of freedom](https://discourse.julialang.org/t/derivatives-of-b-spline-w-r-t-their-degrees-of-freedom/87997)

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**Author:** [@touste](https://discourse.julialang.org/u/touste)\
**Replies:** 3\
**Last updated:** [September 30, 2022, 9:25pm UTC](https://discourse.julialang.org/t/derivatives-of-b-spline-w-r-t-their-degrees-of-freedom/87997 "2022-09-30T21:25:31Z")

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Hi all, I’m trying to approximate a shape described by a set of 3D points with a smooth interpolant, I’ve settled on a parametric B-Spline. I’ve got a set of 3D points P\_i: using GeometryBasics P₁ = Point3(0.0, 0.0, 0…

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## [Boundary intervals for splines using CompactBases](https://discourse.julialang.org/t/boundary-intervals-for-splines-using-compactbases/71344)

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**Author:** [@Dan.phi](https://discourse.julialang.org/u/Dan.phi)\
**Replies:** 4\
**Last updated:** [November 24, 2021, 11:44am UTC](https://discourse.julialang.org/t/boundary-intervals-for-splines-using-compactbases/71344 "2021-11-24T11:44:08Z")

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I want to implement natural cubic splines in Julia via B-splines (which are a basis for splines). I found CompactBases.jl, which uses B-splines and allows me to evaluate the basis functions at a value x. Now, let the se…

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## [Multi Dimensional Cubic Spline](https://discourse.julialang.org/t/multi-dimensional-cubic-spline/71687)

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**Author:** [@tgautam03](https://discourse.julialang.org/u/tgautam03)\
**Replies:** 3\
**Last updated:** [November 18, 2021, 5:20am UTC](https://discourse.julialang.org/t/multi-dimensional-cubic-spline/71687 "2021-11-18T05:20:30Z")

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Hi, I’ve a multi dimensional dataset (3 features and 1 label) and want to interpolate using cubic splines. I have found several documentations on interpolation in 2D but can’t find anything that’ll help with this. Lookin…

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## [How to find crossing point using Spline1D in julia?](https://discourse.julialang.org/t/how-to-find-crossing-point-using-spline1d-in-julia/71364)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 2\
**Last updated:** [November 12, 2021, 9:38am UTC](https://discourse.julialang.org/t/how-to-find-crossing-point-using-spline1d-in-julia/71364 "2021-11-12T09:38:08Z")

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I have fitted a spline function using Spline1D from the package Dierckx to the data: x = \[0.0, 0.25167322597331027, 1.6518531853618088, 4.032506892599284, 6.871304792339401, 10.090447889235595, 13.686254426579751, 17.61…

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## [My code for cubic spline interpolation plots different image everytime and not smooth](https://discourse.julialang.org/t/my-code-for-cubic-spline-interpolation-plots-different-image-everytime-and-not-smooth/70564)

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**Author:** [@pessoalzy](https://discourse.julialang.org/u/pessoalzy)\
**Replies:** 4\
**Last updated:** [October 28, 2021, 8:12pm UTC](https://discourse.julialang.org/t/my-code-for-cubic-spline-interpolation-plots-different-image-everytime-and-not-smooth/70564 "2021-10-28T20:12:38Z")

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I wrote following code trying to implement a cubic spline interpolation (clamped spline). Every time I run it on jupyter notebook may plot different image. And the plotting is likely not very smooth, which is weird for c…

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## [\[ANN\] CatmullRom.jl (centripetal splines)](https://discourse.julialang.org/t/ann-catmullrom-jl-centripetal-splines/26755)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 0\
**Last updated:** [July 24, 2019, 8:10pm UTC](https://discourse.julialang.org/t/ann-catmullrom-jl-centripetal-splines/26755 "2019-07-24T20:10:15Z")

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CatmullRom.jl is an easily used approach to fast, attractive curvilinear blending. Catmull-Rom splines are a mathematical workhorse of computational graphics, animation and visualization. Applied to a sequence of points,…

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## [\[ANN\] NormalSplines.jl: 1-D Interpolating Normal Splines](https://discourse.julialang.org/t/ann-normalsplines-jl-1-d-interpolating-normal-splines/36811)

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**Author:** [@igorkohan](https://discourse.julialang.org/u/igorkohan)\
**Replies:** 0\
**Last updated:** [March 31, 2020, 6:37pm UTC](https://discourse.julialang.org/t/ann-normalsplines-jl-1-d-interpolating-normal-splines/36811 "2020-03-31T18:37:21Z")

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NormalSplines.jl package implements the normal splines method for interpolating a function based on data of the function values and its first or second derivatives known at a set of points. The normal splines method con…

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## [Using splines in a likelihood](https://discourse.julialang.org/t/using-splines-in-a-likelihood/49340)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 0\
**Last updated:** [October 30, 2020, 10:47pm UTC](https://discourse.julialang.org/t/using-splines-in-a-likelihood/49340 "2020-10-30T22:47:27Z")

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I am looking to add splines to the type of functions that can go in @formula to support a conditional likelihood model I’ve developed. Once that is working I plan to add automatic smoothing parameter selection. The pac…

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## [Find intersection between curves in julia](https://discourse.julialang.org/t/find-intersection-between-curves-in-julia/70494)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 13\
**Last updated:** [October 28, 2021, 7:20am UTC](https://discourse.julialang.org/t/find-intersection-between-curves-in-julia/70494 "2021-10-28T07:20:56Z")

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Hello, I have two curves with the values: col\_y = \[8.02511788606e7, 9.98481296252e7, 2.328332483329e8, 6.148181496526e8, 9.453171952624e8, 1.2331292887706e9, 1.4394296796998e9, 1.460066157955e9, 1.3570403824485e9, 1.42…

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## [Best method for calculating the second derivative of 1D array](https://discourse.julialang.org/t/best-method-for-calculating-the-second-derivative-of-1d-array/69353)

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**Author:** [@AngusRussell](https://discourse.julialang.org/u/AngusRussell)\
**Replies:** 11\
**Last updated:** [October 20, 2021, 7:45pm UTC](https://discourse.julialang.org/t/best-method-for-calculating-the-second-derivative-of-1d-array/69353 "2021-10-20T19:45:06Z")

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Essentially I have 1D arrays of eigenvalues as shown in the above plot and I want to find the 2nd derivative of each energy band with respect to ϵ. My current method uses Dierckx.jl. In my code, the eigenvalues are …

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## [High-order derivatives of sampled data](https://discourse.julialang.org/t/high-order-derivatives-of-sampled-data/67045)

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**Author:** [@DanielIngraham](https://discourse.julialang.org/u/DanielIngraham)\
**Replies:** 9\
**Last updated:** [September 1, 2021, 5:38pm UTC](https://discourse.julialang.org/t/high-order-derivatives-of-sampled-data/67045 "2021-09-01T17:38:53Z")

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Hi, I have discrete data sampled at a constant rate. I need the first, second, and third derivatives with respect to time. Is there a Julia package that could help me do that? Things that I’ve considered so far: Use f…

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## [Multi-threading and Dierckx.jl & Interpolations.jl and gradients](https://discourse.julialang.org/t/multi-threading-and-dierckx-jl-interpolations-jl-and-gradients/67452)

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**Author:** [@gianmariomanca](https://discourse.julialang.org/u/gianmariomanca)\
**Replies:** 6\
**Last updated:** [September 1, 2021, 6:15am UTC](https://discourse.julialang.org/t/multi-threading-and-dierckx-jl-interpolations-jl-and-gradients/67452 "2021-09-01T06:15:55Z")

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I noticed that if I use https://github.com/kbarbary/Dierckx.jl (1D, k=3 and derivatives) in a loop with the Threads.@threads macro I get partially corrupted results. If I remove the Threads.@threads macro results look f…

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## [Building a cubic spline interpolator using points and specifying derivatives](https://discourse.julialang.org/t/building-a-cubic-spline-interpolator-using-points-and-specifying-derivatives/64238)

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**Author:** [@donkeysaddle](https://discourse.julialang.org/u/donkeysaddle)\
**Replies:** 6\
**Last updated:** [July 8, 2021, 7:49pm UTC](https://discourse.julialang.org/t/building-a-cubic-spline-interpolator-using-points-and-specifying-derivatives/64238 "2021-07-08T19:49:01Z")

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Is there a way to build a cubic spline in either Interpolations.jl or Dierckx.jl (or somewhere else) where you can set what the derivatives should be at specified points. Ideally, these derivatives would not have to be a…

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## [\[ANN\] NormalHermiteSplines.jl v.0.4.0](https://discourse.julialang.org/t/ann-normalhermitesplines-jl-v-0-4-0/57554)

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**Author:** [@igorkohan](https://discourse.julialang.org/u/igorkohan)\
**Replies:** 8\
**Last updated:** [March 22, 2021, 4:18pm UTC](https://discourse.julialang.org/t/ann-normalhermitesplines-jl-v-0-4-0/57554 "2021-03-22T16:18:49Z")

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Multivariate Normal Hermite-Birkhoff Interpolating Splines in Julia This announces the v0.4.0 release of NormalHermiteSplines.jl package that implements the normal splines method for solving the following interpolation …

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## [Smoothing interpolation for tachometer data](https://discourse.julialang.org/t/smoothing-interpolation-for-tachometer-data/56117)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 29\
**Last updated:** [March 3, 2021, 9:14pm UTC](https://discourse.julialang.org/t/smoothing-interpolation-for-tachometer-data/56117 "2021-03-03T21:14:56Z")

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In rotating machinery analysis, tachometer signals are often collected. If a 1 pulse per revolution tachometer is sampled at the same frequency as the vibration signal, then there is some jitter in the tachometer signal…

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