package username.tests;

import java.io.PrintWriter;
import username.analysis.Graph;
import username.util.Mathematician;

/**
 * A class that helps analyze the various exponentiation algorithms.
 *
 * @author Samuel A. Rebelsky
 * @version 1.1 of April 2006
 */
public class AnalyzeExpt
{
  // +-----------+-----------------------------------------------
  // | Constants |
  // +-----------+

  /**
   * The number of times to repeat a test so that too-quick tests
   * aren't too fast to measure.
   */
  private static final int REPETITIONS = 1000;

  /**
   * The largest n to use.
   */
  private static final int MAXN = 1000;

  /**
   * The increment to n at each step.
   */
  public static final int INCREMENT(int n)
  {
    return 2*n + 1;
  } // INCREMENT(int)


  // +-------+---------------------------------------------------
  // | Tests |
  // +-------+

  public static void main(String[] args)
    throws Exception
  {
    double x = 2.7;
    PrintWriter pen = new PrintWriter(System.out, true);
    Graph g = new Graph(70,30);

    // Try a variety of exponents for one version.
    pen.println("Analyzing exptFor");
    pen.println("n\ttime in microseconds");
    for (int n = 0; n < MAXN; n = INCREMENT(n)) {
      long start = System.currentTimeMillis();
      for (int rep = 0; rep < REPETITIONS; rep++) {
        double result = Mathematician.exptFor(x,n);
      } // for
      long finish = System.currentTimeMillis();
      long time = 1000*(finish-start)/REPETITIONS;
      pen.println(n + "\t" + time);
      g.plot(n,(int) time);
    } // for each exponent
    pen.println();

    g.setPlotChar('+');
    pen.println("Analyzing exptWhile");
    pen.println("n\ttime in microseconds");
    // Try a variety of exponents for one version.
    for (int n = 0; n < MAXN; n = INCREMENT(n)) {
      long start = System.currentTimeMillis();
      for (int rep = 0; rep < REPETITIONS; rep++) {
        double result = Mathematician.exptWhile(x,n);
      } // for
      long finish = System.currentTimeMillis();
      long time = 1000*(finish-start)/REPETITIONS;
      pen.println(n + "\t" + time);
      g.plot(n,(int) time);
    } // for each exponent
    pen.println();

    // Draw the graph
    pen.println(g);
  } // main(String[])

} // class AnalyzeExpt