code: public Vec getRow(int r)
      {
          if(r < 0 || r >= rows())
              throw new ArithmeticException("Row was not a valid value " + r + " not in [0," + (rows()-1) + "]");
          DenseVector c = new DenseVector(cols());
          for(int j =0; j < cols(); j++)
              c.set(j, get(r, j));
          return c;
      }
docs: Creates a vector that has a copy of the values in row <i>i</i> of this
  matrix. Altering it will not effect the values in <i>this</i> matrix.
  @param r the row to copy
  @return a clone of the row as a {@link Vec}