# \#approximation

**URL:** https://discourse.julialang.org/tag/approximation/1441.md

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## [Floating-point accuracy visualization example: the ULP error for each math function coming with Julia](https://discourse.julialang.org/t/floating-point-accuracy-visualization-example-the-ulp-error-for-each-math-function-coming-with-julia/135392)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 20\
**Last updated:** [February 6, 2026, 2:25pm UTC](https://discourse.julialang.org/t/floating-point-accuracy-visualization-example-the-ulp-error-for-each-math-function-coming-with-julia/135392 "2026-02-06T14:25:29Z")

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Introduction The implementation of a math function, such as cos(::Float64) in Julia, should be fast, but also needs to be at least somewhat accurate. Here I propose a method for visualizing empirical accuracy data. Cons…

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## [Approximate implicit function on real line](https://discourse.julialang.org/t/approximate-implicit-function-on-real-line/125421)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 7\
**Last updated:** [February 3, 2025, 2:31pm UTC](https://discourse.julialang.org/t/approximate-implicit-function-on-real-line/125421 "2025-02-03T14:31:38Z")

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I have a family of functions y(x) defined implicitly by x = \\log\\left(\\sum\_{i=1}^N \\exp(a\_i + y b\_i) \\right) where 0 \< b\_1 \< \\dots \< b\_N can be assumed. It is easy to find the solution numerically (eg with Newton’s m…

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## [Multivariate polynomial regression of discrete data in L-infinity norm](https://discourse.julialang.org/t/multivariate-polynomial-regression-of-discrete-data-in-l-infinity-norm/125369)

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**Author:** [@CeterisPartybus](https://discourse.julialang.org/u/CeterisPartybus)\
**Replies:** 16\
**Last updated:** [January 31, 2025, 1:10am UTC](https://discourse.julialang.org/t/multivariate-polynomial-regression-of-discrete-data-in-l-infinity-norm/125369 "2025-01-31T01:10:55Z")

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Hi everyone, Does anyone know of a Julia package that implements polynomial approximations (preferably Chebyshev polynomials) given data on a multivariate function with a L-infinity norm? Specifically, I have x, f(x) p…

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## [\[ANN\] RationalFunctionApproximation.jl](https://discourse.julialang.org/t/ann-rationalfunctionapproximation-jl/104118)

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**Author:** [@tobydriscoll](https://discourse.julialang.org/u/tobydriscoll)\
**Replies:** 6\
**Last updated:** [September 22, 2023, 4:23pm UTC](https://discourse.julialang.org/t/ann-rationalfunctionapproximation-jl/104118 "2023-09-22T16:23:39Z")

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I am pleased to announce the initial release of RationalFunctionApproximation.jl, which provides automatic rational function approximation in the complex plane. It uses an updated version of the AAA algorithm (Driscoll,…