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Add Barnes-Hut optimization to Atlas2 NAD layout#733

Merged
flo-dup merged 207 commits intomainfrom
693-barnes_hut
Mar 17, 2026
Merged

Add Barnes-Hut optimization to Atlas2 NAD layout#733
flo-dup merged 207 commits intomainfrom
693-barnes_hut

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@NathanDissoubray NathanDissoubray commented Sep 29, 2025 •
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Please check if the PR fulfills these requirements

  • The commit message follows our guidelines
  • Tests for the changes have been added (for bug fixes / features)
  • Docs have been added / updated (for bug fixes / features)
  • A PR or issue has been opened in all impacted repositories (if any)

Does this PR already have an issue describing the problem?

Closes #693
Waiting for the merge of #721

What kind of change does this PR introduce?

This PR adds a faster calculation of the repulsion force (known as Barnes-Hut) for Atlas2 in the NAD, which allows the bigger network like an 8k nodes to be done in less than 100s. Networks of less than 1000 nodes are done in less than 1s.
Those numbers do not include any potential post-processing (such as an overlap prevention, which might add 1 or 2 seconds of calculation on top of that).

What is the current behavior?

Networks of 8k nodes take about 2k-3k seconds, networks of 1k nodes take about 8s

What is the new behavior (if this is a feature change)?

image Some networks don't have as much as a gain as others, those are the networks where we can see a torsion in the graph (basically it forms an X), so Barnes-Hut can't optimize as much because nodes are in a less favorable position). We still gain time for all graph with this method though. The visual does not change in any noticeable way.

Does this PR introduce a breaking change or deprecate an API?

  • Yes
  • No

If yes, please check if the following requirements are fulfilled

  • The Breaking Change or Deprecated label has been added
  • The migration steps are described in the following section

What changes might users need to make in their application due to this PR? (migration steps)

Other information:

@NathanDissoubray
Remove the use of the springRepulsionFactor
99efb3f 
This was used to push nodes away from the center of the edge between
other nodes. The goal of this was to reduce edge crossing, but it just
pushes edge crossings to the the side, instead of the middle of edges
(not removing the edge at all). This is usually less readable because
edge crossings are closer to actual nodes, and it also makes
calculations longer.

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Fix copyright to javadoc format
c41e222 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Rename Vector to Vector2D to avoid confusion with java.util.Vector
43e2c1e 
Also change Vector2D to a record to simplify the code

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Refactor in a geometry package
61cea98 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add edge and graph
0fc40a2 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Test geometry package
f4c12a9 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Rename graph to ForceGraph, use JGraphT graph to manage vertex and edges
ba03e9d 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Delete GraphTest as the graph is managed by JGraphT
6acc17e 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add some forces
7ec20e2 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add GraphTestData to not need to rewrite the network each time
65618c8 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Test Vector2D
6daa11c 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add some forces and force parameters
7d35702 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Remove the optimized version of the call to the force
89fe4e7 
Make a class for each way to calculate the force instead, store the
artifacts needed for that in the class directly

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add coulomb force
c1a2fe4 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add layout parameters
9d0c1ec 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Add a way to keep all the springs parameter in the diagram and start …
ef8d9e0 
…to define SpringyAlgorithm

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Store parameters inside the force instead of passing it as a paramete…
393e187 
…r each time

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Finish the calculation of the layout for springy
116fa78 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Make the setup for springy
bd0063f 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Remove springRepulsion in copied code after rebase
899ac68 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Enum in separate files
5fca781 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Make the LayoutAlgorithmRunner
10fa06f 
There is no optimization or post-processing yet, that will come later

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Make bounding box min be bottom and max be top instead of the opposite
13f43fe 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Test graph creation
cb28929 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Test coulomb force
949b488 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Make a new simple setup
f371ea8 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
getter setter for origin
6daabd5 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Gravity force simple test
655ac6f 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Test gravityforce by edge number
ef89cb1 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Reformat test
4a5fea2 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Actually remove check, not just comments about the check
8d8741d 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Change the childrenNodeIdFlatten to directly return all index that ar…
9555f2a 
…e not NO_CHILDREN

Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Create nodes closer to where they are actually used in the code
848a701 
Note: this creates a bit of code duplication
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Modify some RefObj to Ref
cec00de 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Merge branch 'main' into 693-barnes_hut
a019129
@NathanDissoubray
Change test files after merge
3e63761 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Adapt Barnes-Hut to remove repulsionForceFromFixedPoints
72f3f5c 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Put the barycenter in the quadtree node instead of having a separate …
29a9f5c 
…list

Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Remove useless parameter
7d92621 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Fix tests, remove TODO
ab26f06 
The TODO was mentionned in the stoppingCriteria interface issue

Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
flo-dup
flo-dup requested changes Mar 10, 2026
View reviewed changes
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Vector2D.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java
Comment thread diagram-util/src/main/java/com/powsybl/diagram/util/layout/geometry/Quadtree.java Outdated
@NathanDissoubray
Fix object creation default in Vector2D
5de8c62 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Directly use an IntStream instead of having to mapToInt in Quadtree
fd17d09 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Replace array with int fields in QuadtreeNode
59342ec 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Do not repeat getting the node with index
518915f 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Avoid resizing the list of nodes by creating it with an adequate size
10dea7a 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Use sublist instead of array
33ac185 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Use Collections::swap instead of manually swapping points in quadtree…
c3fcdd1 
… construction

Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Use a better initial capacity for node array
7de4171 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
add scaleFactor for Atlas2
b0f5455 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Directly create barycenter point
c50e2e6 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray NathanDissoubray mentioned this pull request Mar 16, 2026
Merged
8 tasks
@NathanDissoubray
Check for null on postProcessing
08194aa 
Signed-off-by: Nathan Dissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Change setNodeBarycenter to createNodeBarycenter (to match createLeaf…
6c578ba 
…Barycenter)

Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@NathanDissoubray
Merge branch 'main' into 693-barnes_hut
f9035a3
@NathanDissoubray
Remove TODO
f04cd76 
Signed-off-by: NathanDissoubray <nathan.dissoubray@rte-france.com>
@sonarqubecloud
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sonarqubecloud Bot commented Mar 17, 2026

Quality Gate Passed Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
92.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

@flo-dup flo-dup merged commit e336ced into main Mar 17, 2026
8 checks passed
@flo-dup flo-dup deleted the 693-barnes_hut branch March 17, 2026 15:15
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Rewrite of the layout calculation algorithm for the Network Area Diagram

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@NathanDissoubray @flo-dup