source: branches/3106_AnalyticContinuedFractionsRegression/HeuristicLab.Algorithms.DataAnalysis/3.4/ContinuedFractionRegression/Vector.cs

using System;

namespace HeuristicLab.Algorithms.DataAnalysis.ContinuedFractionRegression {
  public class Vector {
    private double[] _components;
    private int _nDimensions;
    public Vector(int dimensions) {
      _components = new double[dimensions];
      _nDimensions = dimensions;
    }

    public int NDimensions {
      get { return _nDimensions; }
    }

    public double this[int index] {
      get { return _components[index]; }
      set { _components[index] = value; }
    }

    public double[] Components {
      get { return _components; }
    }

    /// <summary>
    /// Add another vector to this one
    /// </summary>
    /// <param name="v"></param>
    /// <returns></returns>
    public Vector Add(Vector v) {
      if (v.NDimensions != this.NDimensions)
        throw new ArgumentException("Can only add vectors of the same dimensionality");

      Vector vector = new Vector(v.NDimensions);
      for (int i = 0; i < v.NDimensions; i++) {
        vector[i] = this[i] + v[i];
      }
      return vector;
    }

    /// <summary>
    /// Subtract another vector from this one
    /// </summary>
    /// <param name="v"></param>
    /// <returns></returns>
    public Vector Subtract(Vector v) {
      if (v.NDimensions != this.NDimensions)
        throw new ArgumentException("Can only subtract vectors of the same dimensionality");

      Vector vector = new Vector(v.NDimensions);
      for (int i = 0; i < v.NDimensions; i++) {
        vector[i] = this[i] - v[i];
      }
      return vector;
    }

    /// <summary>
    /// Multiply this vector by a scalar value
    /// </summary>
    /// <param name="scalar"></param>
    /// <returns></returns>
    public Vector Multiply(double scalar) {
      Vector scaledVector = new Vector(this.NDimensions);
      for (int i = 0; i < this.NDimensions; i++) {
        scaledVector[i] = this[i] * scalar;
      }
      return scaledVector;
    }

    /// <summary>
    /// Compute the dot product of this vector and the given vector
    /// </summary>
    /// <param name="v"></param>
    /// <returns></returns>
    public double DotProduct(Vector v) {
      if (v.NDimensions != this.NDimensions)
        throw new ArgumentException("Can only compute dot product for vectors of the same dimensionality");

      double sum = 0;
      for (int i = 0; i < v.NDimensions; i++) {
        sum += this[i] * v[i];
      }
      return sum;
    }

    public override string ToString() {
      string[] components = new string[_components.Length];
      for (int i = 0; i < components.Length; i++) {
        components[i] = _components[i].ToString();
      }
      return "[ " + string.Join(", ", components) + " ]";
    }
  }
}