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Adding LoadZIP model component type#362

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pelesh merged 14 commits intodevelopfrom
abirchfield/zip_load
Apr 8, 2026
Merged

Adding LoadZIP model component type#362
pelesh merged 14 commits intodevelopfrom
abirchfield/zip_load

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@abirchfield abirchfield commented Apr 6, 2026 •
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Description

Adding new ZIP load model to phasor dynamics, motivated by the parameter estimation effort.

Proposed changes

  • Documentation of LoadZIP model definition
  • Implementation of LoadZIP model
  • Unit tests for LoadZIP model (Note: because model has no differential variables, implementation tests are not necessary. Also, Jacobian tests were not implemented as these are more complex and require an analytical Jacobian, which we do not have.)
  • Three-bus case example validated against PowerWorld.

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.
  • I have updated CHANGELOG.md to reflect the changes in this PR.

Further comments

None.

@abirchfield abirchfield marked this pull request as draft April 6, 2026 20:29
@abirchfield abirchfield marked this pull request as ready for review April 6, 2026 20:31
pelesh
pelesh requested changes Apr 6, 2026
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I think we need to decide if we are going to stick to the modeling approach we defined in the documentation or go back to more compact implementation as in zip load code.

  • The model as defined in the README file is larger (has additional 2 algebraic variables) but exposes more parallelism.
  • The model as implemented in the C++ code is more compact but requires atomic add to manage system Jacobian assembly.

It would be good to decide what modeling approach to take before merging this PR.

Comment thread GridKit/Model/PhasorDynamics/LoadZIP/LoadZIPImpl.hpp
Comment thread GridKit/Model/PhasorDynamics/LoadZIP/LoadZIPImpl.hpp
Comment thread GridKit/Model/PhasorDynamics/LoadZIP/LoadZIPImpl.hpp
@pelesh pelesh added the question Further information is requested label Apr 6, 2026
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abirchfield commented Apr 7, 2026

Yes, I think the doc approach with Ir and Ii being variables is good.

So far I have not been successful in implementing it. I get Enzyme issues.

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nkoukpaizan commented Apr 7, 2026

Yes, I think the doc approach with Ir and Ii being variables is good.

So far I have not been successful in implementing it. I get Enzyme issues.

What's happening is that in the documented formulation, $\frac{\partial h}{\partial w_b}$ is null. Instead, we'll need $\frac{\partial h}{\partial y}$, $\frac{\partial f}{\partial y}$ and $\frac{\partial f}{\partial w_b}$ terms.

@abirchfield abirchfield marked this pull request as draft April 8, 2026 19:32
@abirchfield abirchfield marked this pull request as draft April 8, 2026 19:32
abirchfield and others added 14 commits April 8, 2026 14:38
@abirchfield
zip load readme v0
310b94b
@abirchfield
fixed latex issue
878c371
@abirchfield
fixed latex issue 2
36d5a80
@abirchfield
fixed latex issue 3
673837b
@abirchfield
added more to zip load docs
96fbf80
@abirchfield
initial implementation of loadzip
5c8b1ea
@abirchfield
initial tests
a3b0901
@abirchfield
Example with ZIP load
16bbfb2
@abirchfield
Apply pre-commmit fixes
32a7f43
@abirchfield
attempting documented approach
decec01
@abirchfield
Apply pre-commmit fixes
1507084
@nkoukpaizan @pelesh @abirchfield
LoadZIP Jacobians for new formulations and tests (#364)
e3a8d58 
* Alternate Jacobian terms for ZIPLoad.

* Jacobian test for LoadZIP.

* Fix phasor_load_zip test call.

* Minor formatting.

* LoadDataZIP --> LoadZIPData in CMakeLists.

* Comment out LoadZIP df/dy for now.

* Apply pre-commmit fixes

* Guard LoadZIPTests.jacobian test with ENABLE_ENZYME.

* Expect failure for LoadZIPTests.

* LoadZIP initialization.

* Fix typo.

* Simplify ifrac expression in LoadZIP.

* Activate df/dy term in LoadZIP with a hack for null df/dy'.

* Apply pre-commmit fixes

* Set correct answer key for LoadZIP test

* Apply pre-commmit fixes

---------

Co-authored-by: nkoukpaizan <nkoukpaizan@users.noreply.github.com>
Co-authored-by: pelesh <peless@ornl.gov>
Co-authored-by: pelesh <pelesh@users.noreply.github.com>
@abirchfield
restored intended test values
f645fa4
@abirchfield
fixed example
44627a4
@abirchfield abirchfield force-pushed the abirchfield/zip_load branch from 74e2035 to 44627a4 Compare April 8, 2026 19:39
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abirchfield commented Apr 8, 2026

Thanks all for your help!

@abirchfield abirchfield marked this pull request as ready for review April 8, 2026 19:43
@abirchfield abirchfield requested a review from pelesh April 8, 2026 19:43
pelesh
pelesh approved these changes Apr 8, 2026
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All issues fixed, good to merge.

@pelesh pelesh merged commit f817d00 into develop Apr 8, 2026
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@abirchfield abirchfield deleted the abirchfield/zip_load branch April 8, 2026 20:30
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@pelesh pelesh pelesh approved these changes

@PhilipFackler PhilipFackler Awaiting requested review from PhilipFackler

@lukelowry lukelowry Awaiting requested review from lukelowry

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@abirchfield @nkoukpaizan @pelesh