コピペ: Newton-Paphson

形式

Plain text

投稿日時

2019-01-15 23:39

公開期間

無期限

 #include<stdio.h>
 #include<stdlib.h>
 #include<math.h>
 
 #define EPS 1.0e-8
 #define POW 2
 
 double Newton(double);
 double Func(double, double);
 double dFunc(double);
 
 int main(){
 
     double Ln = Newton(2.0);//L_1 = sqrt(2)
     printf("%12.10f\n",Ln);
     int n = 1;
     int pow_base = 2;
     int n_max = 20;
 
     while( n < n_max ){ 
         
         printf( "%12.10f\n", pow_base * Ln );
         Ln = Newton( 2-Newton(4 - pow(Ln, 2)) );
         n += 1;
         pow_base *= POW;
 
     }
 
     return 0;
 }
 
 
 //平方根を求める
 double Newton(double C){
     
     double x = C;
     double dx = -Func(x, C) / dFunc(x);
     
     while( fabs(dx) > EPS ){
         x += dx;
         dx = -Func(x, C) / dFunc(x);
     }
 
     return x;
 }
 
 
 double Func(double x, double C){
     return x*x-C;
 }
 
 double dFunc(double x){
     return 2.0 * x;
 }