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MathNet

Performant Linear Algebra Library
Maybe something like this: https://numerics.mathdotnet.com?

Found this in a project I am currently working. Does someone knows the reason to implement it this way?
Math.net Numerics has a lot of that, for this use case it has the extensions AlmostEqual.
MKL.NET
What are some alternatives?
Microsoft Automatic Graph Layout  A set of tools for graph layout and viewing
AngouriMath  Opensource crossplatform symbolic algebra library for C# and F#. One of the most powerful in .NET. Can be used for both production and research purposes.
UnitConversion  Expansible Unit Conversion Library for .Net Core and .Net Framework
Math3D  A .NET Standard 2.0 library for simple and efficient 3D math that is a featurerich replacement for System.Numerics https://vimaec.github.io/Math3D
AutoDiff  A .NET library that provides fast, accurate and automatic differentiation (computes derivative / gradient) of mathematical functions.
GeometRi  Simple and lightweight computational geometry library for .Net
Rationals  🔟 Implementation of rational number arithmetic for .NET with arbitrary precision.