Add Subsystem and Partition Interfaces for PowerElectronics by abdourahmanbarry · Pull Request #560 · ORNL/GridKit

abdourahmanbarry · 2026-08-28T20:36:16Z

Description

In this PR, we implement SubsystemModel for partitioned Power Electronics simulation. The implementation provides the infrastructure required to partition Power Electronics networks, and to evaluate subsystem residuals and Jacobians independently.

This is the third of four stacked pull requests that split PR #492 into simpler, more manageable chunks.

Proposed changes

We added a SubsystemModel class to represent an individual partition and a BusPartitionInterface component to mark partition boundaries. Together, these enable us to partition larger networks for co-simulation and parallel function evaluation.

Checklist

All tests pass.
Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
The new code follows GridKit™ style guidelines.
There are unit tests for the new code.
The new code is documented.
The feature branch is rebased with respect to the target branch.
The CHANGELOG.md has been updated to reflect the changes. If this is a minor PR that is part of a larger fix already included in the file, state so.

superwhiskers

just an architectural question

nkoukpaizan

A few specific comments.

This seems to work, but I find the logic of the BusPartitionInterface constructor and SubsystemModel index maps hard to follow. I would like to get inputs from @alexander-novo on those implementations.

I'll take another look after the initial comments have been addressed.

abdourahmanbarry · 2026-09-19T00:49:09Z

@nkoukpaizan @alexander-novo @superwhiskers I have updated the code to incorporate the suggestions and improved the documentation to make the implementation easier to follow. Let me know what you think.

superwhiskers

just one minor comment

abdourahmanbarry · 2026-10-12T15:40:34Z

@nkoukpaizan I have added the partition interface that we discussed last time. It is simpler (and hopefully more efficient), but it only supports partitioning between a MicrogridBus and a MicrogridLine. I believe this covers the most common use cases for partitioning in cosim for PowerElectronics. I still advice we keep the other partition interface for partitioning test problems that are not necessarily PowerElectronics such as the Hires test problem.

CC: @pelesh @alexander-novo @superwhiskers

superwhiskers

looks good. all of these are nitpicks. SubsystemModelWithHires passes just fine on my machine.

nkoukpaizan

I like the BusLinePartitionInterface. Please see my related comments and other comments below.

…onstructor

read-the-docs-community · 2026-10-30T20:07:13Z

Documentation build overview

📚 GridKit | 🛠️ Build #35628010 | 📁 Comparing a2f18f4 against latest (94c9766)

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28 files changed · + 7 added · ± 21 modified

+ Added

± Modified

nkoukpaizan

A few minor comments. Good to merge after they are addressed.

nkoukpaizan · 2026-11-02T17:42:03Z

+    public:
+      using TimeFunction = std::function<void(ScalarT)>;


I believe the argument should be RealT rather than ScalarT. Does the alias need to be public?

This is address in 60060e8

I left the alias as public as it is used by one of the methods as a parameter type. But it can be made private as well if that is preferable.

Yes, let's keep it private.

Okay, sounds great.

pelesh

This looks good; there are only a few minor things to address before we merge:

Please address comments by @nkoukpaizan and a few comments here (mainly questions on implementation). If the code is intentionally implemented like this, please add comments explaining why. The implementation intent at places I flagged is not quite clear to me.

pelesh · 2026-11-02T21:19:40Z

+      /**
+       *@brief Maps global system connection indices to local subsystem connection indices.
+       */
+      std::unordered_map<IdxT, IdxT> global_to_local_map_;


Why use map here? Why not use vector with mapping indices?

The reason for using a map here is that the keys(global indices) belonging to a partition may not necessarily be contiguous. I am afraid using a vector could require create a large vector, even though only a small fraction of its entries would be used.

pelesh · 2026-11-02T21:29:14Z

+      ~PartitionInterface() = default;
+    };


I believe it should be:

Suggested change

~PartitionInterface() = default;

};

~PartitionInterface() override = default;

};

This is addressed here 3b1ae4f

pelesh · 2026-11-02T21:38:19Z

+        for (component_type* comp : components_)
+        {
+          auto extern_indices = comp->getExternIndices();
+
+          for (IdxT j = 0; j < comp->size(); j++)
+          {
+            if (extern_indices.contains(j))


Could we have instead:

Suggested change

for (component_type* comp : components_)

{

auto extern_indices = comp->getExternIndices();

for (IdxT j = 0; j < comp->size(); j++)

{

if (extern_indices.contains(j))

for (component_type* comp : components_)

{

const auto& extern_indices = comp->getExternIndices();

for (IdxT j = 0; j < comp->size(); j++)

{

if (extern_indices.contains(j))

This is addressed here: 60060e8

pelesh · 2026-11-02T21:47:12Z

+        for (node_type* node : nodes_)
+        {
+          for (IdxT i = 0; i < node->size(); i++)
+          {
+            const IdxT global_connection = node->getNodeConnection(i).idx_;
+
+            if (global_connection != INVALID_INDEX<IdxT>)
+            {
+              global_to_local_map_[global_connection] = local_connection++;
+            }
+          }
+        }


Here, in function buildConnectionMap(), i loops from 0 to node->size(). In allocate(), it loops from 0 to node->getInternalSize(). Why discrepancy?

These two are the same in this case. However, it is good to be consistent. Thank you.
This is addressed here: 60060e8

pelesh · 2026-11-02T21:49:18Z

+        // Map each node's global connection indices to subsystem-local indices,
+        // then set the corresponding state, derivative, and residual pointers.
+        for (node_type* node : nodes_)
+        {
+          for (IdxT i = 0; i < static_cast<IdxT>(node->getInternalSize()); i++)
+          {
+            const IdxT node_global_connection = node->getNodeConnection(i).idx_;
+            const IdxT node_local_connection  = global_to_local_map_.at(node_global_connection);
+


Her in allocate() function, i loops from 0 to node->getInternalSize(), whereas in buildConnectionMap(), an equivalent call loops from 0 to node->size(). Is this intended?

Like the previous comment, this has been addressed here: 60060e8

pelesh · 2026-11-02T21:56:48Z

One compiler warning to fix:

In file included from /Users/55y/src/gridkit/GridKit/tests/UnitTests/PowerElectronics/runPartitionPowerElectronicsTests.cpp:3:
/Users/55y/src/gridkit/GridKit/tests/UnitTests/PowerElectronics/PartitionPowerElectronicsTests.hpp:346:43: warning: implicit conversion changes signedness: 'int' to 'size_type' (aka 'unsigned long') [-Wsign-conversion]
  346 |             auto* partition = partitions_[p];
      |                               ~~~~~~~~~~~ ^
/Users/55y/src/gridkit/GridKit/tests/UnitTests/PowerElectronics/PartitionPowerElectronicsTests.hpp:88:43: note: in instantiation of member function 'GridKit::PowerElectronics::Testing::PartitionPowerElectronicsTests<double, unsigned long>::evaluatePartitions' requested here
   88 |           const auto partition_residual = evaluatePartitions(false);
      |                                           ^
/Users/55y/src/gridkit/GridKit/tests/UnitTests/PowerElectronics/runPartitionPowerElectronicsTests.cpp:11:18: note: in instantiation of member function 'GridKit::PowerElectronics::Testing::PartitionPowerElectronicsTests<double, unsigned long>::residual' requested here
   11 |   result += test.residual();
      |                  ^

The rest of the code compiles cleanly. All tests pass.

- Update method comments - Make node size calls consistent - Change parameter type in ForcingFunction to RealT

nkoukpaizan · 2026-11-04T16:28:43Z

+
+#pragma once
+
+#include <omp.h>


Suggested change

#include <omp.h>

This should not be needed and fails on my machine with GRIDKIT_ENABLE_OPENMP=Off

GridKit/tests/UnitTests/PowerElectronics/PartitionPowerElectronicsTests.hpp:4:10: fatal error: 'omp.h' file not found 4 | #include <omp.h> | ^~~~~~~

That's right. This is address in the following commits.

abdourahmanbarry self-assigned this Aug 28, 2026

abdourahmanbarry force-pushed the abdou/subsystem_model branch from 45b0f43 to c90bae2 Compare September 3, 2026 18:56

nkoukpaizan requested review from alexander-novo, nkoukpaizan and superwhiskers September 3, 2026 20:17

nkoukpaizan added the enhancement New feature or request label Sep 3, 2026

superwhiskers reviewed Sep 3, 2026

View reviewed changes

Comment thread GridKit/Model/PowerElectronics/SubsystemModel.hpp Resolved

abdourahmanbarry force-pushed the abdou/subsystem_model branch from 6b976de to 1ad85a7 Compare September 8, 2026 16:50

Base automatically changed from abdou/clone to develop September 8, 2026 17:51

nkoukpaizan force-pushed the abdou/subsystem_model branch from 1ad85a7 to e23c7ba Compare September 8, 2026 17:51

abdourahmanbarry mentioned this pull request Sep 8, 2026

Initial Implementation of Subsystem Model for Partition Simulation #492

Closed

7 tasks done

nkoukpaizan reviewed Sep 10, 2026

View reviewed changes

superwhiskers reviewed Sep 25, 2026

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Comment thread GridKit/Model/PowerElectronics/PartitionInterface/BusPartitionInterface.cpp Resolved

superwhiskers approved these changes Oct 13, 2026

View reviewed changes

Comment thread GridKit/Model/PowerElectronics/PartitionInterface/BusLinePartitionInterface.cpp Resolved

Comment thread GridKit/Model/PowerElectronics/PartitionInterface/BusLinePartitionInterface.hpp Resolved

Comment thread GridKit/Model/PowerElectronics/SubsystemModel.hpp Resolved

nkoukpaizan reviewed Oct 14, 2026

View reviewed changes

abdourahmanbarry and others added 11 commits October 30, 2026 15:15

Add BusPartitionInterface to define partition boundaries

ee0b1b1

Add SubsystemModel for partition evaluation

ca6fe44

Add HIRES test for SubsystemModel

c315040

Add protected access to SystemModelPowerElectronics

ac8769e

Change external data vector to use GridKit vectors

6c76011

Updated SystemModelPowerElectronics.hpp

a67eef2

Update README.md for Hires problem

3d36c47

Minor update

35af962

Apply pre-commit fixes

239fbdd

Address leak in test

4b4c8b6

Change neg1 to INVALID_INDEX

50c8f26

abdourahmanbarry added 16 commits October 30, 2026 15:18

Bug fix

daba0ee

Update SubsystemModel

ceb7c5c

Add BusLinePartitionInterface

bc769a9

Update CMake

88043c4

Forward time updates to enclosed component in BusPartitionInterface

ccfaa9f

Update SubsystemModel

3de0eba

Remove cloned component and move connection index initialization to c…

768622f

…onstructor

Remove Hires Test problem

b023eb3

Add partition PowerElectronics Test problem

39f879c

Update CMake file in tests

73869f1

Remove BusPartitionInterface as requested during code review

489655c

change "counter" to "index"

3c0aa34

Set f_ext_data_ to zero

4a1235e

Updated SystemModels

b6581b6

Update Interfaces

4f1fa56

Update tests

cde9d74

abdourahmanbarry force-pushed the abdou/subsystem_model branch from 33726c6 to cde9d74 Compare October 30, 2026 20:01

Apply pre-commit fixes

c96a613

nkoukpaizan approved these changes Nov 2, 2026

View reviewed changes

pelesh requested changes Nov 2, 2026

View reviewed changes

abdourahmanbarry added 4 commits November 3, 2026 22:25

Remove HIres problem documentation

9770845

Address reviewer comments in SubsystemModel

60060e8

- Update method comments - Make node size calls consistent - Change parameter type in ForcingFunction to RealT

Mark PartitionInterface destructor as override

3b1ae4f

Link OpenMP to execise parallel function evalution

a2f18f4

nkoukpaizan reviewed Nov 4, 2026

View reviewed changes

abdourahmanbarry and others added 3 commits November 4, 2026 19:15

Removed omp.h in partition power electronics test files

ef8d81c

Change alias to private

b41ec0c

Apply pre-commit fixes

3e9024c

Conversation

abdourahmanbarry commented Aug 28, 2026

Description

Proposed changes

Checklist

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abdourahmanbarry commented Sep 19, 2026 •

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