MATLAB and Octave shouldn’t need any introduction to engineers and people who deal with math problems. You don’t always need a desktop computer to run its code either. Madona is a handy app that lets you compile MATLAB and Octave code on your iPhone. it supports plotting and graphing and has a convenient code editor with syntax highlighting and line numbers.
You can use this app to view program output / errors or simply run your programs. It comes with a language reference to help you along the way. There are some limitations though. Madona requires an internet connect to work. It can handle programs under 20s.[where to get it]