/ebooks/transform-methods-in-applied-mathematics-an-introduction
  (8) Undefined index: host   FrontController.php   line 87     18-7-18   20:13
FrontController->getInstance() # line   16, file: /home/smart/public_html/index.php
  FrontController->__construct() # line   37, file: /home/smart/public_html/core/FrontController.php
    FrontController->loadSettings() # line   51, file: /home/smart/public_html/core/FrontController.php