EDIT (26-12-14):In the Belytschko's EFG code, the domain of influence for uniform distributed node can be calculated using the code below; my question is how to calculate xspac and yspac when the nodes are irregularly distributed?% DETERMINE DOMAINS OF INFLUENCE - UNIFORM NODAL SPACINGdmax=3.5;xspac = Lb/ndivl;yspac = D/ndivw;dm = zeros(2,numnod);dm(1,1:numnod)=dmax*xspac*ones(1,numnod);dm(2,1:numnod)=dmax*yspac*ones(1,numnod);kindly help with idea on how /or source code to determine the influence domain for a domain in 2D or 3D with irregularly distributed nodes in EFG or any other meshfree method. Please refer to the concept proposed by G.R Liu in his book:- Meshfree Methods: Moving beyond the Finite Element Method, Page 24 - 26 (Preview page via Google book at http://goo.gl/fd6wyw)Thank you in advance. 
How to determine the support/influence domain for irregularly distributed nodes in the Element-Free Galekin Method?
finite element;computational geometry;meshless methods