DD.WellWorkover.Cloud/AsbCloudInfrastructure/Services/InterpolationLine.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace AsbCloudInfrastructure.Services
{
    public class InterpolationLine
    {
        private readonly double xSum;
        private readonly double ySum;
        private readonly double xySum;
        private readonly double x2Sum;
        private readonly int count;

        public InterpolationLine(IEnumerable<(double Y, double X)> rawData)
        {
            xSum = rawData.Sum(d => d.X);
            ySum = rawData.Sum(d => d.Y);
            xySum = rawData.Sum(d => d.X * d.Y);
            x2Sum = rawData.Sum(d => d.X * d.X);
            count = rawData.Count();
        }

        public double A =>
            (xSum * ySum - count * xySum) /
            (xSum * xSum - count * x2Sum);

        public double B =>
            (xSum * xySum - x2Sum * ySum) /
            (xSum * xSum - count * x2Sum);


        public bool IsYNotChanges(double upperBound = 0d, double lowerBound = 0d)  =>
                A < upperBound && A > lowerBound;

        public bool IsYIncreases(double bound = 0d) =>
            A > bound;

        public bool IsYDecreases(double bound = 0d) =>
            A < bound;

        public bool IsAverageYLessThanBound(double bound) =>
                (ySum / count) < bound;

        public bool IsAverageYMoreThanBound(double bound) =>
                (ySum / count) >= bound;
    }
}