removeNode

Import a factor graph with five 2-D pose nodes and then visualize the factor graph.

fg = importFactorGraph("fiveNodeFactorGraph.g2o");
show(fg,Legend="on");
title("Five-Node Factor Graph")

lim = axis; 

Get all of the 2-D pose node IDs of the graph and remove the first node in the factor graph.

ids = nodeIDs(fg,NodeType="POSE_SE2")

ids = 1×5

     1     2     3     4     5

[removedNodeID,removedFactorID] = removeNode(fg,ids(1))

removedNodeID = 
1

removedFactorID = 
0

Note that removeNode removed the first node, along with the factor related to it. Show the factor graph again to visualize this change.

show(fg);
title("Node 0 Removed")
axis(lim) % Use previous limits for easier comparison

Now remove the second to last node in the factor graph.

nodeToRemove = ids(end-1)

nodeToRemove = 
4

removedNodeIDs = removeNode(fg,nodeToRemove)

removedNodeIDs = 1×2

     4     5

Note that this time, removeNode removed node 4 in addition to the node 3. This is because node 4 is only connected to node 3 in the factor graph, so removing node 3 would leave node 4 disconnected from the factor graph.

show(fg);
title("Node 3 and Node 4 Removed")
axis(lim);