62 lines
921 B
C
62 lines
921 B
C
#include "solve.h"
|
|
#include "status.h"
|
|
|
|
#include <math.h>
|
|
#include <float.h>
|
|
|
|
status t4_solve (
|
|
double (*f) (double),
|
|
double a, double b,
|
|
double eps, int m, double *x, int *m_it
|
|
) {
|
|
int it = 0;
|
|
status ret = SUCCESS;
|
|
double c = DBL_MAX, y, y_a = f(a), y_b = f(b);
|
|
|
|
if (fabs(y_a) - eps < DBL_EPSILON)
|
|
{
|
|
*x = a;
|
|
return SUCCESS;
|
|
} if (fabs(y_b) - eps < DBL_EPSILON)
|
|
{
|
|
*x = b;
|
|
return SUCCESS;
|
|
} if (fabs(fabs(y_b) - fabs(y_a)) < DBL_EPSILON)
|
|
{
|
|
*x = a;
|
|
return EQUAL;
|
|
}
|
|
|
|
for (it = 0; it < m; ++it)
|
|
{
|
|
c = b - ((b - a) / (y_b - y_a)) * y_b;
|
|
y = f(c);
|
|
|
|
if (fabs(y) - eps < DBL_EPSILON)
|
|
{
|
|
ret = SUCCESS;
|
|
break;
|
|
} else if (fabs(y_a) - fabs(y_b) > DBL_EPSILON)
|
|
{
|
|
a = c;
|
|
y_a = y;
|
|
} else if (fabs(y_b) - fabs(y_a) > DBL_EPSILON)
|
|
{
|
|
b = c;
|
|
y_b = y;
|
|
} else
|
|
{
|
|
ret = EQUAL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (it >= m)
|
|
ret = RUN_TIME;
|
|
|
|
*x = c;
|
|
*m_it = it;
|
|
|
|
return ret;
|
|
}
|
|
|