{"id":303402,"date":"2023-08-25T16:58:07","date_gmt":"2023-08-25T16:58:07","guid":{"rendered":"\/forum\/forums\/topic\/number-of-nodes-incoherent\/"},"modified":"2023-08-25T17:01:36","modified_gmt":"2023-08-25T17:01:36","slug":"number-of-nodes-incoherent","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/number-of-nodes-incoherent\/","title":{"rendered":"Number of nodes incoherent"},"content":{"rendered":"

Hi,<\/span><\/p>\n

I am using PyMAPDL on python to process a modal analysis and optimize it. <\/span>
I solved the same model previously on the software ANSYS Mechanical directly and the number of nodes was 616169 in the software. <\/span>
Then I exported the simulation file using cdwrite with the option “ALL” containing all geometry, material property, load, and component data. Then I loaded it with python and solved it again but I get a small difference in the number of nodes, but the results like eigenfrequencies are the same. The problem is not only the number of nodes is different from what I could see on ANSYS Mechanical, it is also incoherent within some arrays\/variables that I get from APDL. I will explain this more as follows, this is a python code: <\/span><\/p>\n

1)<\/strong> print(mapdl.mesh) <\/span><\/p>\n

Output:<\/span>
ANSYS Mesh<\/span>
  Number of Nodes:              616211<\/span>
  Number of Elements:           322069<\/span>
  Number of Element Types:      220<\/span>
  Number of Node Components:    0<\/span>
  Number of Element Components: 0<\/span><\/p>\n

2)<\/strong>  also when getting the number of nodes using mapdl.mesh.n_node it gives back the same number<\/span><\/p>\n

number_nodes = mapdl.mesh.n_node<\/span>
print(number_nodes) <\/span><\/p>\n

Output: 616211<\/span><\/p>\n

3)<\/strong> However when I store the nodes in an array the length of it which should correspond to the number of nodes is different from we got previously<\/span><\/p>\n

nodes = mapdl.mesh.nodes<\/span>
print(len(nodes))<\/span><\/p>\n

Output: 616256<\/span><\/p>\n

4)<\/strong> using mapdl.db.nodes <\/span><\/p>\n

print(mapdl.db.nodes)
<\/span>
MAPDL Database Nodes
Number of nodes: 616256
Number of selected nodes: 616256
Maximum node number: 616256<\/span><\/p>\n

5) <\/strong>and again when I retrieve the displacements for all the nodes I get an array not matching the number of nodes that I get previously from mapdl.mesh.nodes  ; I get the displacements for 616211 nodes only which is different from 616256<\/span><\/p>\n

all_displacements = mapdl.post_processing.nodal_displacement(“ALL”)<\/span>
print(len(all_displacements))
Output: 616211<\/span><\/p>\n

To put you in context: this is causing me a problem because I have the coordinates of some points where I want to get the displacement. But first what I do is that I determine the closest node to the point and then get the displacement of it from the array all_displacement. But in this case the number of nodes is varying in this interval [1, 616256] and the displacements I get are for only for 616211 nodes. So let’s say I want the displacement for the node number 600000, if I use the nodal displacement array that I get from postprocessing I don’t know if it actually corresponds to the same node. <\/span><\/p>\n

Every help is appreciated. Thank very much in advance. <\/span><\/p>\n","protected":false},"template":"","class_list":["post-303402","topic","type-topic","status-closed","hentry","topic-tag-mesh-nodes","topic-tag-nodal-displacement","topic-tag-nodes-problem-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t