Started Task 4

2025.04.18/01Ex/io_status.h

@@ -4,6 +4,7 @@
 #define ERR_MEM	"Error: Not enough memory!"
 #define ERR_OPEN "Error: Cannot open file"
 #define ERR_READ "Error: Cannot read file"
+#define ERR_FUNC "Error: Algorithm is not applicable!"
 
 typedef enum _io_status
 {

2025.04.18/01Ex/main.c

@@ -1,6 +1,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
+#include <float.h>
+#include <math.h>
 
 #include "array_io.h"
 #include "io_status.h"

2025.04.18/04Ex/Makefile

@@ -0,0 +1,42 @@
+WFLAGS = -fstack-protector-all -W -Wall -Wextra -Wunused \
+-Wempty-body -Wlogical-op -Wold-style-declaration -Wmissing-parameter-type \
+-Wignored-qualifiers -Winit-self -Wshadow -Wtype-limits \
+-Wpointer-arith -Wformat-security -Wmissing-format-attribute -Wformat=1 \
+-Wdeclaration-after-statement -Wbad-function-cast -Wnested-externs \
+-Wmissing-prototypes -Wmissing-declarations -Wold-style-definition \
+-Wcast-align -Werror -pedantic -pedantic-errors -Wfloat-equal \
+-Wwrite-strings -Wno-long-long -std=gnu99 -Wstrict-prototypes \
+-Wmissing-field-initializers -Wpointer-sign
+
+LDFLAGS = -std=gnu99 -mfpmath=sse -O3
+LDLIBS = -lm
+
+ifeq ($(OS),Windows_NT)
+	EXE = exe
+	CLEAN = del
+	LDLIBS += -lssp
+else
+	EXE = out
+	CLEAN = rm -f
+endif
+
+TARGET = a04.$(EXE)
+OBJ = main.o solve.o array_io.o
+
+%.o: %.c
+	gcc $(WFLAGS) $(LDFLAGS) -c $< -o $@
+
+$(TARGET): $(OBJ)
+	gcc $^ -o $@ $(LDLIBS)
+
+# Отладочная сборка (gdb)
+gdb: LDFLAGS = -std=gnu99 -mfpmath=sse -g -O0
+gdb: clean $(TARGET)
+
+# Профилировочная сборка (gprof)
+prof: LDFLAGS += -pg
+prof: LDLIBS += -pg
+prof: clean $(TARGET)
+
+clean:
+	$(CLEAN) *.o *$(EXE)

2025.04.18/04Ex/array_io.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <string.h>
+#include "array_io.h"
+
+io_status read_values_and_derivatives (
+		double * restrict X, 
+		double * restrict Y, 
+		double * restrict D, 
+		const int n, 
+		const char * restrict name
+		)
+{
+	FILE *fp;
+	if (!(fp = fopen(name, "r"))) 
+		return ERROR_OPEN;
+
+	for (int i = 0; i < n; ++i)
+		if (fscanf(fp, "%lf\t%lf\t%lf", X + i, Y + i, D + i) != 3)
+		{ fclose(fp); return ERROR_READ; }
+
+	fclose(fp);
+	return SUCCESS;
+}
+
+void print_values_and_derivatives (
+		const double * restrict X, 
+		const double * restrict Y, 
+		const double * restrict D, 
+		const int n, const int p
+		) 
+{
+	int np = (n > p ? p : n);
+
+	for (int i = 0; i < np; i++)
+		printf("f(%lf) = %lf, f`(%lf) = %lf\n", X[i], Y[i], X[i], D[i]);
+}
+

2025.04.18/04Ex/array_io.h

@@ -0,0 +1,20 @@
+#ifndef ARRAY_IO_H
+#define ARRAY_IO_H
+
+#include "io_status.h"
+
+io_status read_values_and_derivatives (
+		double * restrict X, 
+		double * restrict Y, 
+		double * restrict D, 
+		const int n, 
+		const char * restrict name
+		);
+void print_values_and_derivatives (
+		const double * restrict X, 
+		const double * restrict Y, 
+		const double * restrict D, 
+		const int n, const int p
+		);
+
+#endif

2025.04.18/04Ex/io_status.h

@@ -0,0 +1,16 @@
+#ifndef IO_STATUS_H
+#define IO_STATUS_H
+
+#define ERR_MEM	"Error: Not enough memory!"
+#define ERR_OPEN "Error: Cannot open file"
+#define ERR_READ "Error: Cannot read file"
+#define ERR_FUNC "Error: Algorithm is not applicable!"
+
+typedef enum _io_status
+{
+	SUCCESS,
+	ERROR_OPEN,
+	ERROR_READ
+} io_status;
+
+#endif

2025.04.18/04Ex/main.c

@@ -0,0 +1,97 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <float.h>
+#include <math.h>
+
+#include "array_io.h"
+#include "io_status.h"
+#include "solve.h"
+
+/* ./a.out x_0 n filename */
+int main(int argc, char *argv[])
+{
+	double x_0, t, r = 0, *X = 0, *Y = 0, *D = 0;
+	int n, task = 4;
+	char *name = 0;
+	io_status ret;
+
+	if (
+			!((argc == 4) && 
+			sscanf(argv[1], "%lf", &x_0) == 1 &&
+			((sscanf(argv[2], "%d", &n) == 1) && n > 0) &&
+			((name = argv[3]) && name))
+	) {
+		fprintf(stderr, "Usage: %s x_0 n filename\n", argv[0]);
+		return 1;
+	}
+
+	X = (double *)malloc(n * sizeof(double));
+	if (!X)
+	{
+		fprintf(stderr, "%s\n", ERR_MEM);
+		return 2;
+	}
+	
+	Y = (double *)malloc(n * sizeof(double));
+	if (!Y)
+	{
+		free(X);
+		fprintf(stderr, "%s\n", ERR_MEM);
+		return 2;
+	}
+
+	D = (double *)malloc(n * sizeof(double));
+	if (!D)
+	{
+		free(X);
+		free(Y);
+		fprintf(stderr, "%s\n", ERR_MEM);
+		return 2;
+	}
+
+	ret = read_values_and_derivatives(X, Y, D, n, name);
+	do {
+		switch (ret)
+		{
+			case SUCCESS:
+				continue;
+			case ERROR_OPEN:	
+				fprintf(stderr, "%s '%s'!\n", ERR_OPEN, name);
+				break;
+			case ERROR_READ:
+				fprintf(stderr, "%s '%s'!\n", ERR_READ, name);
+				break;
+		}
+
+		free(X);
+		free(Y);
+		free(D);
+
+		return 3; 
+	} while (0);
+
+	t = clock();
+	r = t4_solve(x_0, n, X, Y, D);
+	t = (clock() - t) / CLOCKS_PER_SEC;
+
+	if (fabs(r - DBL_MAX) < DBL_EPSILON)
+	{
+		fprintf(stderr, "%s\n", ERR_FUNC);
+
+		free(X);
+		free(Y);
+		free(D);
+
+		return 4;
+	}
+		
+	printf("%s : Task = %d Result = %e Elapsed = %.2f\n", argv[0], task, r, t);
+
+	free(X);
+	free(Y);
+	free(D);
+
+	return 0;
+}
+

2025.04.18/04Ex/solve.c

@@ -0,0 +1,80 @@
+#include "solve.h"
+
+#include <float.h>
+#include <math.h>
+#include <stdio.h>
+
+// Newton's interpolation polynomial with derivative
+double t4_solve (
+		const double x_0, const int n, 
+		const double * restrict X, 
+		double * restrict Y,
+		double * restrict D
+		)
+{
+	double value, start_value;
+	double x_j = X[n-1];
+	double y_j = Y[n-1];
+
+	for (int i = n-2; i >= 0; --i)
+	{
+		const double x_i = X[i];
+		const double y_i = Y[i];
+		
+		if (fabs(x_j - x_i) < DBL_EPSILON)
+			return DBL_MAX;
+		
+		Y[i+1] = (y_j - y_i) / (x_j - x_i);
+//		printf ("I = %d, f(x%d, ... , x%d) = %lf\n", i, i-k+1, i+2, Y[i+1]);
+
+		y_j = y_i;
+		x_j = x_i;
+	}
+
+	for (int k = 0; k < n-1; ++k)
+	{
+		double f_j = D[n-1];
+
+//		printf ("------- K = %d -------\n", k);
+		
+		for (int l = n*2-2; l >= k; --l)
+		{
+			const int i = l>1;
+			const double x_i = X[i-k];
+			double f_i;
+			x_j = X[i+1];
+			
+			if (fabs(x_j - x_i) < DBL_EPSILON)
+				return DBL_MAX;
+			
+			if (l & 1)
+			{	
+				f_i = D[i];
+				Y[i+1] = (f_j - f_i) / (x_j - x_i);
+			} else
+			{
+				f_i = Y[i];
+				D[i+1] = (f_j - f_i) / (x_j - x_i);
+			}
+			
+			f_j = f_i;	
+			
+//			printf ("I = %d, f(x%d, ... , x%d) = %lf\n", i, i-k+1, i+2, Y[i+1]);
+		}
+	}
+
+	start_value = 1;
+	value = 0;
+
+	for (int i = 0; i < n; ++i)
+	{
+		const double x_i = X[i];
+		value += Y[i] * start_value;
+		start_value *= (x_0 - x_i);
+		value += D[i] * start_value;
+		start_value *= (x_0 - x_i);
+	}
+
+	return value;
+}
+

2025.04.18/04Ex/solve.h

@@ -0,0 +1,11 @@
+#ifndef SOLVE_H
+#define SOLVE_H
+
+double t4_solve (
+		const double x_0, const int n, 
+		const double * restrict X, 
+		double * restrict Y,
+		double * restrict D
+		);
+
+#endif