OpenSoure_Repos/TheAlgorithms-C
1
0
Fork 0
mirror of https://github.moeyy.xyz/https://github.com/TheAlgorithms/C.git synced 2023-10-11 15:56:24 +08:00
Code Issues Packages Projects Releases Wiki Activity

doxygen documentation

Browse Source
This commit is contained in:
Krishna Vedala 2020-05-25 18:26:18 -04:00
parent b2632cdcad
commit 0044830bbc
No known key found for this signature in database
GPG Key ID: BA19ACF8FC8792F7
1 changed files with 20 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
numerical_methods/newton-raphson-root.c
View File

@ -1,6 +1,7 @@
/***
* approximate solution for f(x) = 0
* given f(x) and f'(x)
/**
* @file
* Find approximate solution for \f$f(x) = 0\f$ using
* Newton-Raphson interpolation algorithm.
**/
#include <stdio.h>
@ -10,38 +11,46 @@
#include <limits.h>
#include <complex.h> /* requires minimum of C99 */
#define ACCURACY 1e-10 /**< solution accuracy */
/**
* f(x)
* Return value of the function to find the root for.
* \f$f(x)\f$
*/
double complex function(double complex x)
double complex func(double complex x)
{
return x * x - 3.; /* x^2 = 3 - solution is sqrt(3) */
// return x * x - 2.; /* x^2 = 2 - solution is sqrt(2) */
}
/**
* f'(x)
* Return first order derivative of the function.
* \f$f'(x)\f$
*/
double complex d_function(double complex x)
double complex d_func(double complex x)
{
return 2. * x;
}
/**
* main function
*/
int main(int argc, char **argv)
{
const double accuracy = 1e-10;
double delta = 1;
double complex cdelta = 1;
/* initialize random seed: */
srand(time(NULL));
/* random initial approximation */
double complex root = (rand() % 100 - 50) + (rand() % 100 - 50) * I;
unsigned long counter = 0;
while (delta > accuracy && counter < ULONG_MAX)
/* iterate till a convergence is reached */
while (delta > ACCURACY && counter < ULONG_MAX)
{
cdelta = function(root) / d_function(root);
cdelta = func(root) / d_func(root);
root += -cdelta;
counter++;
delta = fabs(cabs(cdelta));
@ -59,7 +68,7 @@ int main(int argc, char **argv)
}
double r = creal(root);
double c = fabs(cimag(root)) < accuracy ? 0 : cimag(root);
double c = fabs(cimag(root)) < ACCURACY ? 0 : cimag(root);
printf("Iter %5lu: Root: %4.4g%c%4.4gi\t\tdelta: %.4g\n", counter, r,
c >= 0 ? '+' : '-', c >= 0 ? c : -c, delta);