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# Linear Regression with Math.NET and .Net Core 3.1

I recently decided to dust off an old stock data analysis tool that I build a couple years ago and have been updating some code to use readily available tools more, as opposed to hand rolling loads of code for math that i could do easily by hand but would inevitably be buggy and need maintenance if I wrote it from scratch. Enter linear regression.Part of the goal is to detect fluctuations of a particular type so I can research particular stocks in a targeted fashion, so I need a trend line calculation. Simple regression is fine for me, so I’m aiming for the old standby from algebra, y = mx + b. This is served nicely by the MathNet.Numerics library available on NuGet.

Spin up a new console app with a clever name…something like LinearRegressionExample of course. Then add the NuGet package called MathNet.Numerics. I use .Net Core 3.1 in mine but it targets mutliple .Net Frameworks, so it should work with just about anything you throw it at.

What I need is a slope and intercept. This is calculated and returned as a Tuple by the Fit.Line method. We’ll call it thusly in the main method of the sample program.

``````static void Main(string[] args)
{
double[] ydata = new double[] { 157.0800, 158.9865, 158.1200, 155.1100 };
double[] xdata = new double[] { 1, 2, 3, 4 };

Tuple<double, double> p = Fit.Line(xdata, ydata);
double b = p.Item1;
double m = p.Item2;
Console.WriteLine(\$"y={m}x+{b}");
}``````

Nothing Fancy, I just needed a simple test and a fast proof so I could write this into a library for reuse in multiple places in my project.  This particular example gives some long decimal values but that was expected…I did after all choose some MSFT stock data from a few days in Dec 2019 just to be closer to my intended use case.

Cheers ## By Jim Pusateri

Software Developer and Scientist

## One reply on “Linear Regression with Math.NET and .Net Core 3.1”

X Transpose * y = X Transpose * X * p Basic linear regression ..using matrices

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