The very first trouble I faced, while moving the blog from WordPress.com hosting to WordPress.org, was due to a bug in WordPress’s OPML importer. The ‘importer’ messed up with all LaTeX equations on this site — just by deleting a single but very important string from all LaTeX codes. If you are really moving your WordPress content from one blog to other and you have mathematical codes or any other type of coding like C, Perl, PHP and Unix stuffs, then you must read this otherwise you may face the same issues like me. The WordPress OPML importer deletes backslash$“\” from all your posts/pages and media descriptions. A math-blogger knows how important is the backlash for LaTeX/TeX typesetting.$ $The post, which looked like this earlier changed into this after I imported it.$

## What did I after the mess?

At first sight, I thought it was some ‘connection error’ or a ‘temporary importing’… I tried to re-import the OPML file. After that, I tried ‘exporting’ the file again from WordPress.com blog and imported to this, once again.  After all the things I tried, including a new WordPress.com Importer, the results were the same. Incorrect parsing of formulas were everywhere and I had to correct all of them.  I had to re-edit each and every mathematical formula which should have a backslash in it. Since backslash is used to define all special characters and the formatting in equations — which are about 30% of total math-content— you need to waste a lot of time correcting them. To save time, I decided to copy all the content from WordPress.com drafts to WordPress.org editor. This manual editing took six-random days to bring blog back on the track.

# Where is the fault?

The exported .xml file is correct and backslashes are still in that, as you can see here:

This means they were deleted during the import . Just in case, I thought someone from the importer team will correct it, hence I opened a support ticket on WordPress forums, but the support-response was a nil.

## WordPress LaTeX to MathJax?

WordPress LaTeX (known as WPLaTeX) is a part of Jetpack for WordPress developed the Automattic. It render the LaTeX codes into png files and increases load on the server. MathJax works on JavaScript and it doesn’t make that much of load on the servers, as it works directly from the browser, i.e., if your browser supports simple javascript, you can enjoy mathjax. 🙂 I decided to use MathJaX instead of WPLaTeX due to dark and printable parsing of formulas. WPLaTeX looks very ugly on print.