about the nodes of a boundary.

Hello,
Can anybody help?

I want to get the nodes of the special boundary for a flow flux calculaton, but how to get the number of the boundary nodes? If feflow define the boundary  a special number for every boundary nodes? where and which stype are the data of boundary saved? Can I get the nodes of the boundary by the stored data?

Thanks much!

alltimes.

alltimes,

I'm not completely sure how to understand your question, therefore I provide two different answers:

1. If you refer to nodes at the model boundary, you can use the functions IfmGetNumberOfBorders, IfmGetNumberOfBorderNodes, IfmIsExteriorBorder, and IfmGetBorderNode. You find a description of these in Appendix B of the IFM part in the online help.

2. In case you refer to nodes with boundary conditions, iterate over all nodes and check them for boundary conditions with IfmGetBCFlowType.

Good luck
Peter

Hello Peter,

Thanks!
I want to calculate the flow flux of a boundary, and I found that there was a API function like that:IfmGetFlowValueOfGroupIdAtCurrentTime, so I think I would to get the number of nodes for the boundary, and then use the function to calculate the flux.
Maybe I should use IfmGetNumberofBorderNodes.But how to give the parameter --(int nBorder) of the function?

Do you know the better method to calculate the flux?

Best Regards
alltimes

someon use the following code  to get the nodes of a boundary:

for(i=j=0;i<IfmGetNumberOfNodes(pDoc);i++)
    if(IfmIsNodeInGroup(pDoc,i,0))
    node[j++]=i;
    number_of_boundary_nodes=j;

When using the function of IfmIsNodeInGroup,the group was existing before or created at the time?If it was exist,how to create it and give the number to the group?

If I get the numbers of the border by the API function of IfmGetNumberOfBorders,I just can't affirm that the nodes was on the boundary I want concerned.How to confirm this?

The 'groups' options refer to Observation Point Groups in the FEFLOW user interface.

My problem has too many nodes on the border,so it has some trouble to set a group Id by hand. So, I try to use the function IfmGetNumberOfBorderNodes and IfmGetBorderNoder.But how to select the border?On the user interface?How to do it?

If you want to do this for a specific part of the border, you have to define somehow the nodes that belong to this part. As there is no IFM access to observation point groups, I would recommend to use a nodal reference distribution for this.

Do you just mean the "reference data->reference distribution"?Or the "Reference data->observation point group"?Which one  would I choose?

reference distribution