LineEval Routines

Summary

Evaluates linear function.

Unit
RegModels

Declaration

Function LineEval(const B: array of TSample; X: TSample): TSample;

Result

b[0] + b[1]*X for given value X and parameters in B array.

Example 1

Evaluate linear function for single x.

  Uses RegModels, Math387;
  procedure Example;
    var y: TSample;
  begin
    y := LineEval([1,3], 2.5);
    // Res = 1+ 3*2.5 = 8.5
  end;

  #include "Math387.hpp"
  #include "RegModels.hpp"
  void __fastcall Example();
  {
    double y = LineEval(OPENARRAY(TSample,(1.0, 3.0)),2.5);
  }

  using Dew.Stats.Units;
  namespace Dew.Examples
  {
    private void Example()
    {
      RegModels.PowerEval(new double[] {1.0, 3.0}, 2.5);
    }
  }

Declaration

Procedure LineEval(const B: array of TSample; X, YHat: TVec);

Description

Evaluates b[0] + b[1]*X for given values in X vector, parameters in B array, and returns the results in XHat vector. Size and Complex properties of XHat vector are adjusted automatically.

Use this version if you want to evaluate linear function for multiple values at the same time. This is a lot faster than calling single value version for each x value.

See Also
LineDeriv
LineFit

Example 1

Evaluate linear function for multiple values at the same time.

  Uses MathExpr, MtxVecTee, Series, RegModels;
  procedure Example(Series1: TLineSeries);
    var Y,X: Vector;
  begin
    X.Size(100);
    X.Ramp(-5.0, 0.05); // x= -5.0, -4.95, ... -0.05
    // Y = b[0] + b[1]*X
    LineEval([1,3],X,Y);
    DrawValues(X,Y,Series1,false);
  end;

  #include "Math387.hpp"
  #include "RegModels.hpp"
  #include "MathExpr.hpp"
  #include "MtxVecTee.hpp"
  void __fastcall Example(TLineSeries* series);
  {
    Vector X,Y;
    X->Size(100,false);
    X->Ramp(-5.0, 0.1); // x= -5.0, -4.9, ..., +4.9
    LineEval(OPENARRAY(TSample,(1.0, 3.0)),X,Y);
    DrawValues(X,Y,series,false);
  }

  using Dew.Math;
  using Dew.Stats.Units;
  namespace Dew.Examples
  {
    private void Example()
    {
      Vector X = new Vector(100,false);
      Vector Y = new Vector(0);
      X.Ramp(-5.0, 0.1);
      RegModels.LineEval(new double[] {1.0, 3.0}, X, Y);
    }
  }

Declaration

Procedure LineEval(B, X, YHat: TVec);