Thanks for your quick reaction. The problem for me is not how to code but how to convert the text into program code. I know the basics of PHP and I can even code quite difficult things but I don't understand the text with the instructions. I have to add Singular Value Decomposition and matrices to my PHP code and I don't know how. My deficiency seems to be the mathematical part ... I really want to commit and I don't want you to code it for me. I'm just looking for help because I have problems coding that.