Efficiently removing multiple nodes satisfying custom predicate from rtree

[vnair81]

I need to remove multiple nodes from rtree which satisfy a custom predicate for which I am currently doing the following:

1. Run a query with the custom predicate and accumulate the node values
2. Sequentially remove each node by its value

This looks inefficient as each rtree node must be visited once for step 1 and then for each identified node, it must again be found in the rtree by the remove method in step 2.

Is there a more efficient method which I could employ?

[awulkiew]

Yes, you're correct. This is inefficient. Currently there is no other way.

[vnair81]

Another problem I encountered with the current remove is that if two nodes have the same value, it will remove either of the two. To remove both I can pass the same value twice to remove. However if I want to remove only one but not the other, there is no way for me to specify which of the two I want removed. It will remove the first one that it finds.

In my usage, I add a rtree node for each node in my application's DOM. When one of the DOM node changes, I have to update it in rtree which I am attempting by remove followed by insert. But because of this arbitrary removal, sometimes the other (unchanged) node gets removed.

Would implementing something similar to std::remove_if to accommodate predicates be feasible in the current implementation?

[awulkiew]

You could pass your own EqualTo (see the docs). You could also store pair/tuple of e.g. Box and some id allowing the default EqualTo to distinguish between objects. Would this work for you?

[vnair81]

Thanks @awulkiew.
Default EqualTo worked with tuple.