Klasse SquareMatrix

/** SquareMatrix:
 *    quadratic matrix of doubles
 */

public class SquareMatrix extends Matrix {
    
  /** creates an n x n square matrix */
  public SquareMatrix(int n) {
    super(n,n);
  }
    
  /** matrix multiplication of square matrices gives a square matrix */
  public void mult(SquareMatrix b, SquareMatrix result) {
    super.mult(b, result);
  }
    
  /** returns the trace of a square matrix */
  public double trace() {
    double tr = 0.0;
    for (int i = 0; i < nRows; i++) {
      tr += val[i + nRows * i];
    }
    return tr;
  }
}