title: Eigen Increment Column by One
body: <p>How to increment a column of a dynamic matrix by one, as an in place operation (without creating copies/intermediates) ?</p>
  
  <p>Attempt:</p>
  
  <pre><code>#include &lt;Eigen/Dense&gt;
  #include &lt;iostream&gt;
  #include &lt;stdint.h&gt;
  int main(void){
      Eigen::MatrixXf A;
      A = Eigen::MatrixXf::Random(3, 5);
      std::cout &lt;&lt; A &lt;&lt; std::endl &lt;&lt; std::endl;
      A.col(1) = A.col(1)*2; //this works.
      A.col(1) = A.col(1) + 1; //this doesn't work.
      std::cout &lt;&lt; A &lt;&lt; std::endl;
  }
  </code></pre>