LU

来源：互联网发布：windows己遇关键问题编辑：程序博客网时间：2024/04/27 15:26
#include < stdio.h > #include < math.h > #define N 4#define FO "%-10.5g"void scanfm(float * a, int m, int n, char aa) {    int i,    j;    for (i = 0; i < m; i++) for (j = 0; j < n; j++) {        printf("%c[%d][%d]=", aa, i + 1, j + 1);        scanf("%f", a + i * n + j);    }}void printm(float * a, int m, int n, char aa) {    int i,    j,    k;    printf("%c=\n", aa);    for (i = 0; i < m; i++) {        for (j = 0; j < n; j++) {            k = i * n + j;            if (fabs(a[k]) <= 1e-6) a[k] = 0.0;            printf(FO, a[k]);        }        printf("\n");    }}int lu(float * a, const int n, float * l, float * u) {    int i,    j,    k;    int p;    float r;    for (i = 0; i < n; i++) {        for (j = i; j < n; j++) {            p = i * n + j;            r = 0.0;            for (k = 0; k <= i - 1; k++) r += l * u[k * n + j];            u[p] = a[p] - r;        }        for (j = i + 1; j < n; j++) {            p = j * n + i;            r = 0.0;            for (k = 0; k <= i - 1; k++) r += l[j * n + k] * u[k * n + i];            if (fabs(u) <= 1e-5) return 0;            l[p] = (a[p] - r) / u;        }    }    return 1;}void main(void) {    static float A[N][N],    L[N][N],    U[N][N];    int i,    j;    for (i = 0; i < N; i++) L = 1.0;    scanfm(A[0], N, N, 'A');    printm(A[0], N, N, 'A');    i = lu(A[0], N, L[0], U[0]);    if (i == 0) printf("A can't be resoled!");    else {        printm(L[0], N, N, 'L');        printm(U[0], N, N, 'U');    }}
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