Histogram.java

Go to the documentation of this file.

package edu.rice.cs.hpc.viewer.graph;

import java.util.Arrays;


/************************************************************
 * Class to compute histogram data: bins, frequency, ...
 * @author laksonoadhianto
 *
 ************************************************************/
public class Histogram {
    
    // data for histogram graph
    private double freq[];
    private double axis_x[];
    
    // histogram property
    private double data_min, data_max, data_width;
    
    
    /***
     * create histogram data
     * 
     * @param n_bins: number of bins
     * @param data: array of data
     */
    public Histogram(int n_bins, double data[]) {

        double sorted_data[] = data.clone();
        Arrays.sort(sorted_data);
        data_min = sorted_data[0];
        data_max = sorted_data[data.length-1];
        
        data_width = ((data_max - data_min) / n_bins);
        
        freq = new double[n_bins];
        axis_x = new double[n_bins];
        
        //---------------------------------
        // initialize frequency and axis
        //---------------------------------
        for (int i=0; i<n_bins; i++) {
            freq[i] = 0.0;
            axis_x[i] = data_min + (i * data_width);
        }
        
        //---------------------------------
        // compute the frequency
        //---------------------------------
        for (int i=0; i<data.length; i++) {
            int pos = (int) ( (data[i]-data_min) / data_width);
            if (pos >= n_bins)
                pos = n_bins - 1;
            freq[pos]++;
        }
        
    }
    
    
    /***
     * get the x-axis labels
     * @return
     */
    public double[] getAxisX() {
        return this.axis_x;
    }
    
    
    /****
     * get the frequency values
     * @return
     */
    public double[] getAxisY() {
        return this.freq;
    }
    
    
    /****
     * get the minimum data value
     * @return
     */
    public double min() {
        return data_min;
    }
    
    
    /****
     * get the maximum data value
     * @return
     */
    public double max() {
        return data_max;
    }
    
    public double getWidth() {
        return data_width;
    }
}