How to find nodes in 2D mesh like "by adjacent"?

Hi,

Thanks to all of you for your valuable time and efforts putting in helping others.

I want to redefine smooth for 2D mesh.So i need to get adjacent points of a point(It seems to be connected by a line),like:

*createmark nodes 1 nodeid
*appendmark nodes 1 'by adjacent'
set nodelist  [hm_getmark nodes 1]

Unfortunately，it is not acceptable for node.I spent a lot of time looking for this function but couldn't find it.

If you know how to do this, it will save me a lot of time.I am very grateful for your help!

Thank you very much!!!