title: c++ filling matrix boost
body: <p>hi i've looked into the vector duplicate of this but couldn't find answer</p>
  
  <pre><code>ublas::matrix&lt;int&gt; input;
  fill(input.begin1(), input.end1(), in_val);
  fill(input.begin2(), input.end2(), in_val);
  </code></pre>
  
  <p>but it gives me </p>
  
  <blockquote>
    <p>[2,3] {(3,3,3) (3,0,0)}</p>
  </blockquote>
  
  <p>as you can guess i just want to fill all of it with <code>init_val=3</code> , Thanks.</p>