source: src/main/java/bargainingchips/utilityfunctions/UtilityHelperMethods.java@ 339

package bargainingchips.utilityfunctions;

import bargainingchips.Chip;
import bargainingchips.ChipIssueValue;

/**
 * 
 * This class contains mathematical methods helping computational procedures mostly in utility functions, 
 * namely, 
 *  - Bezier            // mathematical curve
 *  - comb                      // mathematical combination 
 *  - fc                        // mathematical factorial
 *  - uSlope            // y value respected to x value at a sloped line
 *  - writeT            // String list of values (e.g., prices, quantities, etc) assigned to a single variable (e.g. {@link Chip}) 
 * 
 * 
 * @author Faria Nassiri-Mofakham
 *
 */

public class UtilityHelperMethods<T> 
{
        /**
         * @param input parameter (e.g., an offered price per a {@link Chip}, 
         *                and `n' data points of type T (e.g., as of Double[], Integer[], etc).
         * 
         * @return Bezier value of rank `n' for the offered parameter.
         **/
        public double bezier(T[] desired, Double offered)  
        {
                double bez = 0.0;
                int n= desired.length;
                for (int i=0; i<n; i++)
                {
                        bez = ( (offered < (double) desired[0]) ? 1.0 : ( (offered > (double) desired[n-1]) ? 0.0 : comb(n,i)*Math.pow(1-offered, n)*Math.pow(i, n)*(double)desired[i]));
                }
                return ( (bez>1) ? 1 : (bez<0) ? 0 : bez);
        }
        
        /**
         * @return combination of `n' and `k'
         **/
        public int comb(int n, int k)  
        {
                return fc(n)/(fc(n-k)*fc(k));
        }

        /**
         * @return factorial of `n'
         **/
        public int fc(int n) {  
                int result = 1;
                for (; n > 1; n--) {
                        result *= n;
                }
                return result;
        }
        
        /**
         * @param a param and 2 data points and respected utilities, showing a sloped line
         * @return utility of param
         **/    
        public double uSlope(double param, T tData1, T tData2, Double uData1, Double uData2)
        {
                Double data1 = (Double) tData1; 
                Double data2 = (Double) tData2;

                return (param-data1)*(uData1-uData2)/(data1-data2)+uData1;
        }
        
        /**
         * @return an String list of values assigned to a single variable, e.g. list of quantities or prices per a {@link Chip}
         **/
        public String writeT(ChipIssueValue<T[]> t)
        {
                String s = "{";
                T[] j;
                for (Chip c: t)
                {
                        s += " " + c.toString() + "={";
                        j= t.getUnitValue(c);
                        //System.out.println("j: "+j);
                        for (int k=0; k<j.length; k++)
                                s += j[k].toString()+((k<j.length-1) ? ", " : "");
                        s += "}";
                }       
                s += " }";
                return s;
        }
}