[英]Why is my for loop not running 5 times for h[i]?
void LAPLACEWCG() {
int i, j, m, n, cnt;
double err, rx, ry, ave, a, b, hx, hy, tol, max1,err_metric;
tol = 0.000000001;
max1 = 100000000;
double h[5] = {0.1, 0.05, 0.01, 0.005, 0.001};
for(int loop = 0; loop < 5; loop++)
{
hx = h[loop];
hy = h[loop];
printf("hx = %lf\n",hx);
a = 1;
b = 1;
n = (a / hy) + 1;
m = (b / hx) + 1;
double *X = (double *) malloc(m * sizeof(double));
double *Y = (double *) malloc(n * sizeof(double));
double **R = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
R[i] = (double *) malloc(m * sizeof(double));
double **P = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
P[i] = (double *) malloc(m * sizeof(double));
double **AP = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
AP[i] = (double *) malloc(m * sizeof(double));
double **U = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
U[i] = (double *) malloc(m * sizeof(double));
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
U[i][j] = 1;
}
}
for (j = 0; j < m; j++) {
X[j] = j * hx;
}
for (j = 0; j < m; j++) {
}
for (j = 0; j < n; j++) {
Y[j] = (b - (j * hy));
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
R[i][j] = 0.0;
P[i][j] = 0.0;
AP[i][j] = 0.0;
}
}
rx = (1 / (hx * hx));
ry = (1 / (hy * hy));
ave = (a * (BDYVAL(1, 0) + BDYVAL(2, 0)) + b * (BDYVAL(3, 0) + BDYVAL(4, 0))) / (2 * a + 2 * b);
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
U[i][j] = ave * U[i][j];
}
}
for (i = 0; i < n; i++) {
U[i][0] = BDYVAL(3, Y[i]);
U[i][m-1] = BDYVAL(4, Y[i]);
}
for (j = 0; j < m; j++) {
U[0][j] = BDYVAL(1, X[j]);
U[n-1][j] = BDYVAL(2, X[j]);
}
U[0][0] = (U[0][1] + U[1][0]) / 2;
U[0][m-1] = (U[0][m - 2] + U[1][m-1]) / 2;
U[n-1][0] = (U[n - 2][0] + U[n-1][1]) / 2;
U[n-1][m-1] = (U[n - 2][m-1] + U[n-1][m - 2]) / 2;
for (j = 1; j < m-1; j++) {
for (i = 1; i < n-1; i++) {
R[i][j] = (rx * U[i][j + 1] + rx * U[i][j - 1] + ry * U[i + 1][j] + ry * U[i - 1][j]
- 2 * (rx + ry) * U[i][j]);
}
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
P[i][j] = R[i][j];
}
}
err = ERROR_METRIC(R, m * n, 3);
while ((err > tol) && (cnt <= max1)) {
for (j = 1; j < m-1; j++) {
for (i = 1; i < n-1; i++) {
if (j == 1) {
if (i == 1) {
AP[i][j] = -rx * P[i][j + 1] - ry * P[i + 1][j] + 2 * (rx + ry) * P[i][j];
} else if (i == n - 2) {
AP[i][j] = -rx * P[i][j + 1] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
} else {
AP[i][j] = -rx * P[i][j + 1] - ry * P[i + 1][j] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
}
} else if (j == m - 2) {
if (i == 1) {
AP[i][j] = -rx * P[i][j - 1] - ry * P[i + 1][j] + 2 * (rx + ry) * P[i][j];
} else if (i == n - 2) {
AP[i][j] = -rx * P[i][j - 1] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
} else {
AP[i][j] = -rx * P[i][j - 1] - ry * P[i + 1][j] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
}
} else if (i == n - 2) {
AP[i][j] = -rx * P[i][j + 1] - ry * P[i][j - 1] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
} else if (i == 1) {
AP[i][j] = -rx * P[i][j + 1] - ry * P[i][j - 1] - ry * P[i + 1][j] + 2 * (rx + ry) * P[i][j];
} else {
AP[i][j] = -rx * P[i][j + 1] - rx * P[i][j - 1] - ry * P[i + 1][j] - ry * P[i - 1][j] + 2 * (rx + ry) * P[i][j];
}
}
}
CGUPDATE(U, R, P, AP, n, m);
err = ERROR_METRIC(R, m * n, 3);
cnt = cnt + 1;
}
if (cnt >= max1) {
printf("Maximum number of iterations exceeded");
}
double **E = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
E[i] = (double *) malloc(m * sizeof(double));
double **D = (double **) malloc(n * sizeof(double*));
for (i = 0; i < n; i++)
D[i] = (double *) malloc(m * sizeof(double));
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
E[i][j] = exp(PI*j*hx)*cos((n-1-i) * hy * PI);
}
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
printf("E[%d][%d]: %lf \n", i, j, E[i][j]);
}
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
printf("U[%d][%d]: %lf \n", i, j, U[i][j]);
}
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
D[i][j] = U[i][j] - E[i][j];
}
}
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
printf("D[%d][%d]: %lf \n", i, j, D[i][j]);
}
}
err_metric = ERROR_METRIC(D,m*n,1);
printf ("h: %lf error metric: %lf\n",hx,err_metric);
}
}
h[5] 的 for 循環應該運行 5 次,但它只執行一次。
我需要用 5 個不同的 h 值遍歷 function 5 次,我還能做些什么嗎?
它沒有給我任何錯誤。
function 的 rest 工作正常。
我在 function 的末尾關閉循環。 在此之前我應該在任何地方關閉它嗎?
我在 for 循環中更改了變量,它仍然只運行一次。
在內部 for 循環中,您正在更改我在外部 for 循環中聲明的變量
for(int i=0; i<5;i++)
{
// ...
for (i = 0; i < n; i++)
//...
在內部 for 循環中使用其他標識符。
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