/*
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);
}
}
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