Absolutly wrong done Task 5

2025.05.02/05Ex/solve.c

@@ -0,0 +1,117 @@
+#include "solve.h"
+
+#include <math.h>
+#include <float.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+int t5_solve (
+		double (*f) (double), 
+		double a, double b, 
+		double eps, int m, double *x
+) {
+	int it;
+	double c = (a + b) / 2;
+
+	double y_a = f(a);
+	double y_c = f(c);
+	double y_b = f(b);
+	
+	if (is_null(y_a))
+		return 1;
+	else if (is_null(y_b))
+		return 1;
+	else if (is_null(y_c))
+		return 1;
+
+	if (is_equal(a, b))
+		return -1;
+	else if (is_equal(a, c))
+	       return -1;
+	else if (is_equal(b, c))
+		return -1;
+
+	for (it = 1; it < m+1; ++it)
+	{
+		double x_new, y_new, *temp_pnt = 0, *inner_max_pnt;
+		const double m_1 = (y_c - y_a) / (c - a);
+		const double m_2 = (y_b - y_c) / (b - c);
+
+		const double A = (m_2 - m_1) / (b - a);
+		const double B = m_1 - A * (a + c);
+		const double C = y_a - a * m_1 + A * a * c;
+		
+		const double D = B * B - 4 * A * C;
+
+		if (is_null(A))
+			return -3;
+		else if (D < -DBL_EPSILON)
+			return -1;
+		else if (D > DBL_EPSILON)
+		{
+			const double sqrt_D = sqrt(D);
+			const double inv_A = 1./(2 * A);
+
+			double x_1 = (-B + sqrt_D) * inv_A;
+			double x_2 = (-B - sqrt_D) * inv_A;
+
+			double y_x_1 = f(x_1);
+			double y_x_2 = f(x_2);
+
+			if (is_eps(y_x_1, eps))
+			{
+				*x = x_1;
+				return it;
+			} else if (is_eps(y_x_2, eps))
+			{
+				*x = x_2;
+				return it;
+			} else if (y_x_2 - y_x_1 > DBL_EPSILON)
+			{
+				x_new = x_1;
+				y_new = y_x_1;
+			} else
+			{
+				x_new = x_2;
+				y_new = y_x_2;
+			}
+		} else
+		{
+			double x_1 = -B / (2 * A);
+			double y_x_1 = f(x_1);
+
+			if (is_eps(y_x_1, eps))
+			{
+				*x = x_1;
+				return it;
+			}
+
+			x_new = x_1;
+			y_new = y_x_1;
+		}
+
+		if (
+			is_equal(x_new, a) ||
+			is_equal(x_new, c) ||
+			is_equal(x_new, b)
+		   )
+			return -1;
+
+		inner_max_pnt = fp_abs_max(&c, &b, &y_c, &y_b, &temp_pnt);	
+		*fp_abs_max(&a, inner_max_pnt, &y_a, temp_pnt, &temp_pnt) = x_new;
+		if (fabs(y_new) - fabs(*temp_pnt) > DBL_EPSILON)
+			return -4;
+		*temp_pnt = y_new;
+	}
+
+	if (it > m)
+		return -2;
+	else
+	{
+		double temp = 0, *temp_x_pnt = fpmax(&c, &b, -y_c, -y_b, &temp);
+		*x = *fpmax(&a, temp_x_pnt, -y_a, temp, &temp);
+		return it;
+	}
+}
+