/**
* Infinity norm
*
* @return maximum row sum.
*/
public double normInf() {
double f = 0;
for (int i = 0; i < m; i++) {
double s = 0;
for (int j = 0; j < n; j++) {
s += Math.abs(A[i][j]);
}
f = Math.max(f, s);
}
return f;
}
/**
* Matrix trace.
*
* @return sum of the diagonal elements.
*/
public double trace() {
double t = 0;
for (int i = 0; i < Math.min(m, n); i++) {
t += A[i][i];
}
return t;
}
/**
* Generate matrix with random elements
*
* @param m Number of rows.
* @param n Number of colums.
* @return An m-by-n matrix with uniformly distributed random elements.
*/
public static Matrix random(int m, int n) {
Matrix A = new Matrix(m, n);
double[][] X = A.getArray();
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
X[i][j] = Math.random();
}
}
return A;
}
/**
* Print the matrix to the output stream. Line the elements up in columns. Use the format object,
* and right justify within columns of width characters. Note that is the matrix is to be read
* back in, you probably will want to use a NumberFormat that is set to US Locale.
*
* @param output the output stream.
* @param format A formatting object to format the matrix elements
* @param width Column width.
* @see java.text.DecimalFormat#setDecimalFormatSymbols
*/
public void print(PrintWriter output, NumberFormat format, int width) {
output.println(); // start on new line.
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
String s = format.format(A[i][j]); // format the number
int padding = Math.max(1, width - s.length()); // At _least_ 1 space
for (int k = 0; k < padding; k++) output.print(' ');
output.print(s);
}
output.println();
}
output.println(); // end with blank line.
}