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added documentation

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Krishna Vedala 2020-05-25 16:36:24 -04:00
parent f097a5d343
commit ec04754b66
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1 changed files with 33 additions and 18 deletions
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51
numerical_methods/durand_kerner_roots.c
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@ -1,3 +1,17 @@
/**
* @file
* Compute riots of any given polynomial.
*
* Test the algorithm online:
* https://gist.github.com/kvedala/27f1b0b6502af935f6917673ec43bcd7
*
* Try the highly unstable Wilkinson's polynomial:
* ```
* ./numerical_methods/durand_kerner_roots.c 1 -210 20615 -1256850 53327946 -1672280820 40171771630 -756111184500 11310276995381 -135585182899530 1307535010540395 -10142299865511450 63030812099294896 -311333643161390640 1206647803780373360 -3599979517947607200 8037811822645051776 -12870931245150988800 13803759753640704000 -8752948036761600000 2432902008176640000
* ```
*/
* /
#include <math.h>
#include <time.h>
#include <stdio.h>
@ -7,22 +21,15 @@
#include <complex.h>
#include "function_timer.h"
/**
* Test the algorithm online:
* https://gist.github.com/kvedala/27f1b0b6502af935f6917673ec43bcd7
#define ACCURACY 1e-10 /**< maximum accuracy limit */
/**
* Evaluate the value of a polynomial with given coefficients
**/
/***
* Try the highly unstable Wilkinson's polynomial:
* ./numerical_methods/durand_kerner_roots.c 1 -210 20615 -1256850 53327946 -1672280820 40171771630 -756111184500 11310276995381 -135585182899530 1307535010540395 -10142299865511450 63030812099294896 -311333643161390640 1206647803780373360 -3599979517947607200 8037811822645051776 -12870931245150988800 13803759753640704000 -8752948036761600000 2432902008176640000
* */
#define ACCURACY 1e-10
/**
* define polynomial function
**/
long double complex poly_function(double *coeffs, unsigned int degree, long double complex x)
long double complex poly_function(double *coeffs, /**< coefficients of the polynomial */
unsigned int degree, /**< degree of polynomial */
long double complex x /*<< point at which to evaluate the polynomial */
)
{
long double complex out = 0.;
unsigned int n;
@ -33,6 +40,10 @@ long double complex poly_function(double *coeffs, unsigned int degree, long doub
return out;
}
/**
* create a textual form of complex number
* \returns pointer to converted string
*/
const char *complex_str(long double complex x)
{
static char msg[50];
@ -44,6 +55,10 @@ const char *complex_str(long double complex x)
return msg;
}
/**
* check for termination condition
* \returns 0 if termination not reached, 1 otherwise
*/
char check_termination(long double delta)
{
static long double past_delta = INFINITY;
@ -69,9 +84,9 @@ int main(int argc, char **argv)
return 0;
}
degree = argc - 1; /*< detected polynomial degree */
coeffs = (double *)malloc(degree * sizeof(double)); /**< store all input coefficients */
s0 = (long double complex *)malloc((degree - 1) * sizeof(long double complex)); /**< number of roots = degree-1 */
degree = argc - 1; /* detected polynomial degree */
coeffs = (double *)malloc(degree * sizeof(double)); /* store all input coefficients */
s0 = (long double complex *)malloc((degree - 1) * sizeof(long double complex)); /* number of roots = degree-1 */
/* initialize random seed: */
srand(time(NULL));