Seidel.c

#include "stdlib.h"
#include "stdio.h"
#include "math.h"

float* seidel(int size, float** A, float eps)
{
    float* x = (float*)malloc(sizeof(float) * size);
    for (int i = 0; i < size; i++)
        x[i] = 0;
    char converge = 0;
    while (!converge)
    {
        float* x_new = (float*)malloc(sizeof(float) * size);
        for (int i = 0; i < size; i++)
            x_new[i] = x[i];

        for (int i = 0; i < size; i++)
        {
            float s1 = 0, s2 = 0;
            for (int j = 0; j < i; j++)
                s1 += A[i][j] * x_new[j];
            for (int j = i + 1; j < size; j++)
                s2 += A[i][j] * x[j];
            x_new[i] = (A[i][size] - s1 - s2) / A[i][i];
        }

        float sum = 0;
        for (int i = 0; i < size; i++)
            sum += (x_new[i] - x[i]) * (x_new[i] - x[i]);
        converge = sqrtf(sum) <= eps;
        free(x);
        x = x_new;
    }

    return x;
}

int main(int argc, char** argv)
{
    int size = 0;
    do {
        printf("Введите порядок матрицы:\n");
        scanf("%d", &size);
    } while (size < 1);

    float** a = (float**)malloc(sizeof(void*) * size);

    printf("Введите матрицу:\n");
    for (int i = 0; i < size; i++)
    {
        a[i] = (float*)malloc(sizeof(float) * (size + 1));
        for (int j = 0; j <= size; j++)
            scanf("%f", &a[i][j]);
    }
    printf("\n");

    float* x = seidel(size, a, 0.001f);
    for (int i = 0; i < size; i++)
    {
        printf("x[%d]=%f\n", i + 1, x[i]);
    }

    return 0;
}