functions.php

<?php // don't include this line

/**
 * Display Posts, category by author name 
 *
 */
function be_dps_category_author_name( $args, $atts ) {
  if( is_user_logged_in() ) {
    $current_user = wp_get_current_user();
    $got_login_name = $current_user->user_login;
    $args['category_name'] = $got_login_name;
  }
  return $args;
}
add_filter( 'display_posts_shortcode_args', 'be_dps_category_author_name', 10, 2 );