[plugin: co_authors-plus] Example of "Related posts"

I wanted to add a “Posts by same author(s)” at the end of my articles. Since I’ve been struggling with this for days and found bits of answers here and there, I thought I could share this so it might help others now that it’s working for me.

<div class="relatedposts">
<?php
$orig_post = $post;
global $post;  

$post_co_authors = get_coauthors( $post->ID );
// build the slugs array
$ca = array();
foreach ($post_co_authors as $c) {
  array_push($ca,'cap-'.$c->user_nicename);
}
$args = array(
  'post_type' => 'post'
  ,'post__not_in' => array($orig_post->ID)
  ,'posts_per_page' => -1
  ,'post_status' => 'publish'
  ,'tax_query' => array(
    array(
      'taxonomy' => 'author'
      ,'field' => 'slug'
      ,'terms' => $ca
    )
  )
);
$q = new wp_query( $args );
if ( $q->have_posts() ) {
  ?>
  <h4>From same author(s)</h4>
  <ul>
  <?php
  while ( $q->have_posts() ) {
    $q->the_post();
    if ($post->ID != $orig_post->ID) {
    ?>
    <li><a rel="external" href="<? the_permalink() ?>"><? the_title(); ?></a></li>
    <?php
  }
}
?>
</ul>
<?php
}
$post = $orig_post;
wp_reset_query();
?>
</div>