InnerProduct

InnerProduct.pas

program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  System.Generics.Collections,
  System.Math;

function InnerProduct(const Vec1: TList<Double>; const Vec2: TList<Double>): Double;
var
  Scalar: TList<Double>;
  Enum1: TList<Double>.TEnumerator;
  Enum2: TList<Double>.TEnumerator;
begin
  if Vec1.Count <> Vec2.Count then
  begin
    raise Exception.Create('Not match dimensions');
  end;

  try
    Scalar := nil;
    Enum1 := nil;
    Enum2 := nil;

    Scalar := TList<Double>.Create();
    Enum1 := Vec1.GetEnumerator;
    Enum2 := Vec2.GetEnumerator;

    while Enum1.MoveNext and Enum2.MoveNext do
    begin
      Scalar.Add(Enum1.Current * Enum2.Current);
    end;

    Result := Sum(Scalar.List);
  finally
    FreeAndNil(Enum1);
    FreeAndNil(Enum2);
    FreeAndNil(Scalar);
  end;
end;

var
  Vec1: TList<Double>;
  Vec2: TList<Double>;
  DevNull: string;
begin
  try
    try
      Vec1 := TList<Double>.Create();
      Vec2 := TList<Double>.Create();

      Vec1.AddRange([1, 2, 3]);
      Vec2.AddRange([4, 5, 6]);

      Writeln(InnerProduct(Vec1, Vec2).ToString);
      Read(DevNull);
    finally
      FreeAndNil(Vec2);
      FreeAndNil(Vec1);
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.