Question

package harp; /** * A simulated harp string, built using the Karplus-Strong algorithm. Sounds like * a synthesizer from the 80s, because that's what it is. * * You'll need to look at the assignment writeup to implement these methods * correctly. * * @author liberato * */ public class HarpString { private final int SAMPLING_RATE = 44100; private final double DECAY_FACTOR = -0.994; /** * Create a harp string of the given frequency, using a sampling rate of * 44,100 Hz; the string is created silent. */ public HarpString(double frequency) { } /** * Create a harp string whose size and initial values are given by the array. */ public HarpString(double[] init) { } /** * Pluck the string by filling the buffer with white noise. */ public void pluck() { } /** * Advance the string simulation one step by running the Karplus-Strong * algorithm. */ public void tic() { } /** * Return the current frequency sample from the string. */ public double sample() { return 0.0; } /** * Return the number of tics passed since this object was initialized. */ public int time() {

return 0; } }

Answer 1

package harp;

/**
* * A simulated harp string, built using the Karplus-Strong algorithm. Sounds
* like * a synthesizer from the 80s, because that's what it is. * * You'll need
* to look at the assignment writeup to implement these methods * correctly. *
* * @author liberato *
*/
public class HarpString {
   private final int SAMPLING_RATE = 44100;
   private final double DECAY_FACTOR = -0.994;
  
   private double[] harp;
   private int count;
   private int ticCount = 0;

   /**
   * * Create a harp string of the given frequency, using a sampling rate of *
   * 44,100 Hz; the string is created silent.
   */
   public HarpString(double frequency) {
      
       int len = (int)Math.round(SAMPLING_RATE/frequency);
      
   harp = new double[len];
  
   }

   /**
   * * Create a harp string whose size and initial values are given by the array.
   */
   public HarpString(double[] init) {
      
int len = (int)Math.round(SAMPLING_RATE/init.length);
      
   harp = new double[len];
  
   for(int i=0;i<init.length;i++)
       harp[i] = init[i];
   count = init.length;
   }
  

   /** * Pluck the string by filling the buffer with white noise. */

   public void pluck() {
      
       //White noise can be recognised by the value around zero.
      
       if(count>0) {
       for(int i=0;i<count;i++) {
          
           harp[i] = Math.random() - 0.5;
          
       }
       }
   }

   /**
   * * Advance the string simulation one step by running the Karplus-Strong *
   * algorithm.
   */
   public void tic() {
      
       if(count>1) {
       double last = this.harp[count-1];
       double lastButone = this.harp[count-2];
double result = ((last+lastButone)/2)*DECAY_FACTOR;
  
this.harp[count-1] = result;
this.ticCount++;
       }
       else
           System.out.println("Tic cannot be performed due to absence of minimum two elements");
  
   }

   /** * Return the current frequency sample from the string. */
   public double sample() {
       //Returning recently added frequency sample
       return this.harp[count-1];
   }

   /** * Return the number of tics passed since this object was initialized. */
   public int time() {

       return this.ticCount;
   }
}

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