how to write matlab code for l2 norm and directional gradient

i need to write code for the function |f| where is l2 norm.also i need to find gradients in north,south,east and west directions.

[Jan]

Currently the best answer is: Yes, you do so. What is the problem?

This means: Please post any details and show, what you have tried so far. It is more likely to get assistance in a forum, when you ask a question about a specific problem. A short story about what you are planning to do does not allow an efficient answer.