The law of Horner

Generate random numbers

Package Cn.xf.algorithm.ch02;import Java.util.arraylist;import java.util.list;/** * Production random number * @author xiaof * */public clas s random {/** * produces a sequence of random numbers * @param n generates n columns * @param m data between 0 and m-1 * @param seed random Initial seed * @param a parameter * @param b parameter * @re  Turn */public static list<integer> randomnum (int n, int m, int seed, int a, int b) {list<integer> numbers = new Arraylist<integer> (); int InitData = (A * seed + B)% M;numbers.add (Math.Abs (InitData));//Initialize a data for (int i = 1; I &l T N ++i) {int NewData = (A * Numbers.get (i-1) + b)% M;numbers.add (Math.Abs (NewData));} return numbers;}     /** * Produces a sequence of random numbers * @param n generates n columns * @param m data between 0 and m-1 * @param seed random Initial seed * @param a parameter * @param b     Parameter * @return */public static list<double> randomnumdouble (int n, int m, int seed, int a, int b) {//Create result array    list<double> numbers = new arraylist<double> (); int InitData = (A * seed + b)% m; Take out an initial value between 0 and M Numbers.add ((double) Math.Abs (InitData));   Add the first value//subsequent value before a data is transformed as the underlying seed for (int i = 1; i < n; ++i) {Double NewData = (A * Numbers.get (i-1) +        b)% m;    Numbers.add (Math.Abs (NewData)); } return numbers;} public static void Main (string[] args) {//list<integer> res = Random.randomnum (10, 10, 998, 58797676, 1);  list<double> res = random.randomnumdouble (ten, 998, 58797676, 1); for (Double a:res) {System.out.print (a + "\ T");} }}

　　

Random coefficient of value

Value evaluation

Package Cn.xf.algorithm.ch06changerule;import Java.util.arraylist;import Java.util.arrays;import java.util.List; Import Org.junit.test;import cn.xf.algorithm.ch02.random;/** * Function: Horner's Law * @author Xiaofeng * @date July 13, 2017 * @fileNam E Hornerrule.java * */public class Hornerrule {/** * Use Horner's law to find a polynomial at a given point value * Input: an n-th polynomial coefficient array P "0...N" (from low to high storage), and a number x * Output: multiple  The value of the formula at x Point * @param p * @param x */public Double Horner (list<double> p, int x) {if (P = = NULL | | p.size () <=0) {return 0d;} Result set Double result = P.get (P.size ()-1); for (int i = P.size ()-2; I >= 0; i) {//accumulate to add coefficient data//one time from large to small bar x coefficient multiplied by x, then add next The coefficients of the number of times rank, and then sum, as a new multiplier for the next number of times result = result * x + p.get (i);} return result;} /** * Normal calculation method * @param p * @param x * @return */public Double nothorner (list<double> p, int x) {if (P = = NULL | | p        . Size () <=0) {return 0d;  }//p is the coefficient store list Double result = 0d;    For the power of 0 (int i = 0; i < p.size (); ++i) {result + = P.get (i) * DOUBLEPOW (x, i); } rEturn result;}        The n power of X is the public static double Doublepow (double x, int n) {if (x = = 0) return 0d;    if (n = = 0) return 1d;    Double result = 1d;    for (int i = 0; i < n; ++i) {result *= x; } return result; @Testpublic void Test1 () {///define an array is the coefficient of the equation, the second parameter is the value of the Unknown//equation: y=5x^5 + 3x^4 + 2x^2 + 3//When x is 4 hornerrule hr    = new Hornerrule ();    list<double> Xishus = new arraylist<double> ();    The order of this array is to be Xishus.addall (Arrays.aslist (3d, 0d, 2d, 0d, 3d, 5d) in the order of 0 power to n Power);    System.out.println (Hr.horner (Xishus, 4));    The general method calculates the System.out.println (Hr.nothorner (Xishus, 4)); System.out.printf ("JOB START OUTPUT:%tf%<tt%n", System.currenttimemillis ());}        @Test public void Compare () {//When x is 4 hornerrule hr = new Hornerrule ();        Build 100 random numbers list<double> Xishus = random.randomnumdouble (600, 3, 998, 58797676, 1); Evaluation System.out.printf ("JOB HORNER START OUTPUT:%tf%<tt%n", System.currenttimemillis ());        System.out.println (Hr.nothorner (Xishus, 3));        System.out.printf ("JOB HORNER END OUTPUT:%tf%<tt%n", System.currenttimemillis ());        System.out.println ("######################################################################################");        System.out.printf ("JOB nothorner START OUTPUT:%tf%<tt%n", System.currenttimemillis ());        System.out.println (Hr.nothorner (Xishus, 3));            System.out.printf ("JOB nothorner END OUTPUT:%tf%<tt%n", System.currenttimemillis ()); }}