когда-то давно лаба такая была
код рабочий, но не красивый)
| Код |
public class Gauss {
private int n;
private double a[][];
private double b[];
Gauss(int n, double a[][], double b[]) {
this.n = n;
this.a = a;
this.b = b;
}
public void gauss_method() {
for (int i = 0 ; i < n; i++) {
if (test1(a, b) == 2)
return;
if (testNull(i, a) == 3)
return;
setOne(i, a, b);
setToFirst(i, a, b);
}
getX(a, b);
}
void printMatrix(double a[][]) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++)
System.out.print(a[i][j] + " ");
System.out.print(b[i]);
System.out.println();
}
System.out.println();
}
private int test1(double a[][], double b[]) {
int k;
for (int i = 0; i < n; i++) {
k = 0;
for (int j = 0; j < n; j++) {
if (a[i][j] == 0)
k++;
}
if (k == 3 && b[i] != 0) {
System.out.println("Нет решений");
System.out.println();
return 2;
}
}
return 1;
}
private int testNull(int k, double a[][]) {
int j = k;
double temp;
while (a[k][j] == 0) {
j++;
if (j == n - 1) {
System.out.println("Деление на ноль");
return 3;
}
for (int i = k; i < n; i++) {
temp = a[k][i];
a[k][i] = a[j][i];
a[j][i] = temp;
temp = b[k];
b[k] = b[j];
b[j] = temp;
}
}
return 1;
}
private void setOne(int k, double[][] a, double[] b) {
try {
for (int i = k + 1; i < n; i++)
a[k][i] = a[k][i] / a[k][k];
b[k] = b[k] / a[k][k];
} catch (Exception e) {
System.out.println("sfdsf");
}
a[k][k] = 1;
}
private void setToFirst(int k, double[][] a, double[] b) {
for (int i = k + 1 ;i < n; i++ ) {
for (int j = k + 1; j < n; j++) {
a[i][j] = a[i][j] / a[i][k] - a[k][j];
}
b[i] = b[i] / a[i][k] - b[k];
a[i][k] = 0;
}
}
public double[] getX(double a[][], double b[]) {
double[] x = new double[n];
double[] no = new double[1];
if (a[n-1][n-1] != 0) {
x[n-1] = b[n-1] / a[n-1][n-1];
}
else {
if (b[n-1] != 0) {
System.out.println("Нет решений");
no[0] = 2;
return no;
}
else {
System.out.println("Бесконечно решений");
no[0] = 3;
return no;
}
}
for (int i = n - 2; i >= 0; i--) {
for (int j = n-1; j > i; j--) {
b[i] = b[i] - a[i][j] * x[j];
}
x[i] = b[i] / a[i][i];
}
for (int i = 0; i < n; i++) {
System.out.println("x[" + (i+1) + "] = " + x[i]);
}
System.out.println();
return x;
}
}
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