# How to Access Neighbor Nodes and Elements

(Difference between revisions)
 Revision as of 14:57, 26 November 2007 (view source)Rrossi (Talk | contribs)← Older edit Revision as of 15:01, 26 November 2007 (view source)Rrossi (Talk | contribs) Newer edit → Line 5: Line 5: [[Image:Neighbours.jpg]] [[Image:Neighbours.jpg]] − we will define as "NEIGHBOUR NODES" of node 910 which share at least one element with node 910 + we will define as "NEIGHBOUR NODES" of node 910 which share at least one element with node 910. To make an example + * Node 910 has the nodes {968 , 940 , 986 , 850 , 876 , 931 } as neighbours nodes + * Node 876 has the nodes {910, 850, 820, 843, 898, 931} as neighbours nodes + ... − {| + and the elements − !  |  Neighbours | + * {2873, 2960, 2961, 2876, 2875, 2874} as NEIGHBOUR ELEMENTS of node 910 − ! Node 910 + * − | 968 | 940 | 986 | 850 | 876 | 931 + − |- + − ! Coord Y + − | 0.0 || 0.51 || 0.27 || 1.77 + − |} +

## Revision as of 15:01, 26 November 2007

In a finite element context it is often useful to have a fast access ( O(N) time with N number of nodes ) to the objects which are "around" a certain node. This can be achieved by storing on each node the list of all of the nodes and elements which are close to it.

Before proceeding it is useful to clarify the meaning of the word "around". To do so, let's consider the mesh

we will define as "NEIGHBOUR NODES" of node 910 which share at least one element with node 910. To make an example

• Node 910 has the nodes {968 , 940 , 986 , 850 , 876 , 931 } as neighbours nodes
• Node 876 has the nodes {910, 850, 820, 843, 898, 931} as neighbours nodes

...

and the elements

• {2873, 2960, 2961, 2876, 2875, 2874} as NEIGHBOUR ELEMENTS of node 910