The simplest polynomial implementation : Polynomial : Development Class C# Source Code

    


/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/

//Compile:
//csc /debug- /o+ /out:polynomial.exe /r:system.dll  Counter.cs Driver.cs PolySimple.cs polynomial.cs ipoly.cs


//File:PolySimple.cs

namespace Polynomial
{
    using System;
    /// <summary>
    /// The simplest polynomial implementation
    /// </summary>
    /// <description>
    /// This implementation loops through the coefficients and evaluates each
    /// term of the polynomial.
    /// </description>
    class PolySimple: Polynomial
    {
        public PolySimple(params double[] coefficients): base(coefficients)
        {
        }

        public override double Evaluate(double value)
        {
            double retval = coefficients[0];
    
            double f = value;

            for (int i = 1; i < coefficients.Length; i++)
            {
                retval += coefficients[i] * f;
                f *= value;
            }
            return(retval);
        }
    }
}

//File:Polynomial.cs
namespace Polynomial
{
    using System;
    using PolyInterface;

        /// <summary>
        /// The abstract class all implementations inherit from
        /// </summary>
    public abstract class Polynomial
    {
        public Polynomial(params double[] coefficients)
        {
            this.coefficients = new double[coefficients.Length];

            for (int i = 0; i < coefficients.Length; i++)
                this.coefficients[i] = coefficients[i];
        }

        public abstract double Evaluate(double value);

        protected double[] coefficients = null;
    }
}
//File:IPoly.cs
namespace PolyInterface
{
        /// <summary>
        /// The interface that implementations will implement
        /// </summary>
    public interface IPolynomial
    {
        double Eval(double value);
    }
}

//File:Driver.cs
namespace Polynomial
{
    using System;
    using System.Diagnostics;

    /// <summary>
    /// Driver class for the project
    /// </summary>
    public class Driver
    {
        /// <summary>
        /// Times the evaluation of a polynomial
        /// </summary>
        /// <param name="p">The polynomial to evaluate</param>
        public static double TimeEvaluate(Polynomial p)
        {
            double value = 2.0;

            Console.WriteLine("{0}", p.GetType().Name);

                // Time the first iteration. This one is done
                // separately so that we can figure out the startup
                // overhead separately...
            long start = Counter.Value;

            p.Evaluate(0.0);    // do the first iteration.
            long delta = Counter.Value - start;
            Console.WriteLine("Overhead = {0:f2} seconds", (double) delta/Counter.Frequency);
            Console.WriteLine("Eval({0}) = {1}", value, p.Evaluate(value));

            int limit = 100000;
            start = Counter.Value;
    
                // Evaluate the polynomial the required number of
                // times.
            double result = 0;
            for (int i = 0; i < limit; i++)
            {
                result += p.Evaluate(value);
            }
            delta = Counter.Value - start;
            
            double ips = (double) limit * ((double)Counter.Frequency / (double) delta);
            Console.WriteLine("Evalutions/Second = {0:f0}", ips);
            Console.WriteLine();

            return(ips);
        }
        /// <summary>
        /// Run all implementations for a given set of coefficients
        /// </summary>
        /// <param name="coeff"> </param>
        public static void Eval(double[] coeff)
        {
            Polynomial[] imps = new Polynomial []
                {
                    new PolySimple(coeff),
            };

            double[] results = new double[imps.Length];
            for (int index = 0; index < imps.Length; index++)
            {
                results[index] = TimeEvaluate(imps[index]);
            }

            Console.WriteLine("Results for length = {0}", coeff.Length);
            for (int index = 0; index < imps.Length; index++)
            {
                Console.WriteLine("{0} = {1:f0}", imps[index], results[index]);
            }
            Console.WriteLine();
        }

        /// <summary>
        /// Maim function.
        /// </summary>
        public static void Main()
        {
            Eval(new Double[] {5.5});

                // Evaluate the first polynomial, with 7 elements
            double[] coeff = 
                new double[] {5.5, 7.0, 15, 30, 500, 100, 1};
            
            Eval(coeff);
            
                // Evaluate the second polynomial, with 50 elements
            coeff = new double[50];
            for (int index = 0; index < 50; index++)
            {
                coeff[index] = index;
            }
            Eval(coeff);
        }
    }
}

//File:Counter.cs
using System;

namespace Polynomial
{
    class Counter 
    {
        public static long Frequency 
        {
            get 
            {
                long freq = 0;
                QueryPerformanceFrequency(ref freq);
                return freq;
            }
        }
        public static long Value 
        {
            get 
            {
                long count = 0;
                QueryPerformanceCounter(ref count);
                return count;
            }
        }

        [System.Runtime.InteropServices.DllImport("KERNEL32")]
        private static extern bool QueryPerformanceCounter(  ref long lpPerformanceCount);

        [System.Runtime.InteropServices.DllImport("KERNEL32")]
        private static extern bool QueryPerformanceFrequency( ref long lpFrequency);                     
    }
}