пропозиції роботи
Przemek Szwajkowski Teleinformatyk
Temat: prośba o sprawdzenie kodu
witam napisałem metode eliminacji gaussa jordana.problem polega na tym że nie chce wczytać pliku//kompilacja javac GaussJordan.java
//uruchomienie java GaussJordan infile outfile
//przykład pliku :
//przykład tablicy 1 (Save the following lines as a text file called in1.)
// 3 5
// 2 0 4 2 9
// 3 4 0 0 -7
// 0 1 0 5 0
//
// przykład tablicy 1 (Save as text file in2.)
// 4 7
// 3.1 4.2 7.9 0.0 0.0 1.1 8.2
// -6.7 1.2 3.4 5.6 7.8 0.0 0.0
// 9.8 7.6 5.4 3.2 2.1 2.3 4.5
// 6.7 8.8 -9.1 2.5 3.6 4.7 -5.5
//
/////////////////////////////////////////////////////////////////////////////////////////////
import java.io.*;
import java.util.StringTokenizer;
class GaussJordan{
// swap()
// swap row i with row k
// pre: A[i][q]==A[k][q]==0 for 1<=q<j
static void swap(double[][] A, int i, int k, int j){
int m = A[0].length - 1;
double temp;
for(int q=j; q<=m; q++){
temp = A[i][q];
A[i][q] = A[k][q];
A[k][q] = temp;
}
}
// divide()
// divide row i by A[i][j]
// pre: A[i][j]!=0, A[i][q]==0 for 1<=q<j
// post: A[i][j]==1;
static void divide(double[][] A, int i, int j){
int m = A[0].length - 1;
for(int q=j+1; q<=m; q++) A[i][q] /= A[i][j];
A[i][j] = 1;
}
// eliminate()
// subtract an appropriate multiple of row i from every other row
// pre: A[i][j]==1, A[i][q]==0 for 1<=q<j
// post: A[p][j]==0 for p!=i
static void eliminate(double[][] A, int i, int j){
int n = A.length - 1;
int m = A[0].length - 1;
for(int p=1; p<=n; p++){
if( p!=i && A[p][j]!=0 ){
for(int q=j+1; q<=m; q++){
A[p][q] -= A[p][j]*A[i][q];
}
A[p][j] = 0;
}
}
}
// printMatrix()
// print the present state of Matrix A to file out
static void printMatrix(PrintWriter out, double[][] A){
int n = A.length - 1;
int m = A[0].length - 1;
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++) out.print(A[i][j] + " ");
out.println();
}
out.println();
out.println();
}
// main()
// read input file, initialize matrix, perform Gauss-Jordan Elimination,
// and write resulting matrices to output file
public static void main(String[] args) throws IOException {
int n, m, i, j, k;
String line;
StringTokenizer st;
// check command line arguments, open input and output files
if( args.length!=2 ){
System.out.println("Usage: GaussJordan infile outfile");
System.exit(1);
}
BufferedReader in = new BufferedReader(new FileReader(args[0]));
PrintWriter out = new PrintWriter(new FileWriter(args[1]));
// read first line of input file
line = in.readLine();
st = new StringTokenizer(line);
n = Integer.parseInt(st.nextToken());
m = Integer.parseInt(st.nextToken());
// declare A to be of size (n+1)x(m+1) and do not use index 0
double[][] A = new double[n+1][m+1];
// read next n lines of input file and initialize array A
for(i=1; i<=n; i++){
line = in.readLine();
st = new StringTokenizer(line);
for(j=1; j<=m; j++){
A[i][j] = Double.parseDouble(st.nextToken());
}
}
// close input file
in.close();
// print array A to output file
printMatrix(out, A);
// perform Gauss-Jordan Elimination algorithm
i = 1;
j = 1;
while( i<=n && j<=m ){
//look for a non-zero entry in col j at or below row i
k = i;
while( k<=n && A[k][j]==0 ) k++;
// if such an entry is found at row k
if( k<=n ){
// if k is not i, then swap row i with row k
if( k!=i ) {
swap(A, i, k, j);
printMatrix(out, A);
}
// if A[i][j] is not 1, then divide row i by A[i][j]
if( A[i][j]!=1 ){
divide(A, i, j);
printMatrix(out, A);
}
// eliminate all other non-zero entries from col j by subtracting from each
// row (other than i) an appropriate multiple of row i
eliminate(A, i, j);
printMatrix(out, A);
i++;
}
j++;
}
// print rank to output file
out.println("rank = " + (i-1));
// close output file
out.close();
}
}
