code: @Override
      public void set( int row , int col , double value ) {
          if( col < 0 || col >= numCols || row < 0 || row >= numRows ) {
              throw new IllegalArgumentException("Specified element is out of bounds: ("+row+" , "+col+")");
          }
  
          data[ row * numCols + col ] = value;
      }
docs: <p>
  Assigns the element in the Matrix to the specified value.  Performs a bounds check to make sure
  the requested element is part of the matrix. <br>
  <br>
  a<sub>ij</sub> = value<br>
  </p>
  
  @param row The row of the element.
  @param col The column of the element.
  @param value The element's new value.