code: public static double elementDiagonalMaxAbs( DMatrixD1 a ) {
          final int size = Math.min(a.numRows,a.numCols);
  
          double max = 0;
          for( int i = 0; i < size; i++ ) {
              double val = Math.abs(a.get( i,i ));
              if( val > max ) {
                  max = val;
              }
          }
  
          return max;
      }
docs: <p>
  Returns the absolute value of the digonal element in the matrix that has the largest absolute value.<br>
  <br>
  Max{ |a<sub>ij</sub>| } for all i and j<br>
  </p>
  
  @param a A matrix. Not modified.
  @return The max abs element value of the matrix.