Adding QUADCOIL integration to DESC as an objective by lankef · Pull Request #2110 · PlasmaControl/DESC

lankef · 2026-03-03T17:14:21Z

This pull request adds two files under /objective, _quadcoil.py and _quadcoil_utils.py. These allows one to call QUADCOIL using a DESC equilibrium and filament coil set as input, and perform quasi-single-stage optimization on the equilibrium and/or the coilset. There are some additions in coils and curves for conversion from simsopt objects. (since quadcoil is written in the simsopt convention). Winding surface can be either fixed or auto-generated, but optimizing the geometry of the winding surface is not yet implemented. The unit test compares quadcoil to desc's built-in REGCOIL.

…also coming soon.

… optimizable_io.py and objective_funs.py to avoid error for static, empty tuple attributes and _objectives with self.coordinates == \'\'

…opy and pasting.

…nversion, but it's not working because quadcoilproxy does not directly store the input dictionary, and desc static dict cannot contain strings (?)

…: Colorbar layout of new layout engine not compatible with old engine, and a colorbar has been created. Engine not changed.

…for merging into main

YigitElma

Thanks fore adding this!
I will review rest of the code later, but it would be nice if you can resolve the problem with CI tests first. It looks like CI and pip in general cannot install quadcoil, I couldn't install it locally either.

YigitElma · 2026-04-24T15:52:57Z

        "_use_jit",
    ]
    _static_attrs = [
+        "_static_attrs",  # A bug as of Oct 10 2025


_static_attrs is already included couple lines below. You probably had to add it before we added in master.

YigitElma · 2026-04-24T15:59:37Z

 def _unmake_hashable(x):
    # turn tuple of ints and shape to ndarray
-    if isinstance(x, tuple) and x[0] == "ndarray":
+    if isinstance(x, tuple) and len(x) and x[0] == "ndarray":


I don't think it hurts to have it, but why did you need this change?

The default values for some QUADCOIL arguments are empty list/tuples (I had to do it because the adjoint derivative is wrapped in a vjp rule before handed to DESC and this way some flows are simpler). Without this check it breaks DESC Optimizable.

YigitElma · 2026-04-24T16:28:13Z

+            metric_name,
+            value_only,
+            verbose,
+    plasma_M_theta : int, optional, default=eq.M_grid


We usually give defaults at the end of the description

YigitElma · 2026-04-24T16:30:14Z

+    bs_chunk_size : int, optional, default=None
+        Size to split Biot-Savart computation into chunks of evaluation points.
+
+    Attributes


These don't seem necessary

YigitElma · 2026-04-24T16:33:15Z

+        # we set them here. This is necessary because we are calling quadcoil
+        # through quadcoil.io.quadcoil_for_diff, which cannot see their default
+        # values in quadcoil.quadcoil.
+        if "net_toroidal_current_amperes" in quadcoil_kwargs.keys():


You can replace all if/else statements by something = dict.pop("something", default)

YigitElma · 2026-04-24T16:41:23Z

+        self._quadcoil_for_diff = jit(_quadcoil_for_diff)
+        self._quadcoil_values = jit(_quadcoil_values)
+        # ----- Setting and registering keyword arguments -----
+        self._static_attrs = _Objective._static_attrs + [


You can move this to line 165, right after docs. We usually define it there

Co-authored-by: Yigit Gunsur Elmacioglu <102380275+YigitElma@users.noreply.github.com>

…maControl/DESC into ffu/quadcoil-qss-pre-commit

…dict popping with defaults using pop(default=**) to improve readability

YigitElma · 2026-05-04T23:18:33Z

@lankef https://github.com/PlasmaControl/DESC/actions/runs/25258105132/job/74060745121?pr=2110 this error happens if you commit a notebook from cluster or after running notebook in Jupyter Lab session (tbh it is very annoying and we have a long standing issue about this #1215, but it is actually not our problem but nbmake or jupyterlab's). You can check this related comment #1498 (comment) for fix. Basically change kernel name of the notebook metadata or just open/save (without running it) on VS code extension.

Merging main changes to branch --------- Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: Yigit Gunsur Elmacioglu <102380275+YigitElma@users.noreply.github.com> Co-authored-by: Kaya Unalmis <kayaunalmis@proton.me> Co-authored-by: Matthew Feickert <matthew.feickert@cern.ch> Co-authored-by: Dario Panici <37969854+dpanici@users.noreply.github.com> Co-authored-by: YigitElma <yigitelmacioglu@gmail.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Dario Panici <dpanici@princeton.edu> Co-authored-by: Rory Conlin <mail@fouriest.net> Co-authored-by: Daniel Dudt <33005725+ddudt@users.noreply.github.com> Co-authored-by: daniel-dudt <daniel.dudt@princetonstellarators.energy> Co-authored-by: Jonathan Brodrick <jonathan.brodrick@simulation.science> Co-authored-by: Wenyin Wei <wenyin.wei.ww@gmail.com> Co-authored-by: Jaydeep Singh <jaydeepsingh15@gmail.com> Co-authored-by: Jonathan Brodrick <jonathanbrodrick@gmail.com> Co-authored-by: Daniel Dudt <135651230+daniel-dudt@users.noreply.github.com> Co-authored-by: issraali <issra.ali@mail.utoronto.ca> Co-authored-by: T.Thun <timothun@web.de>

Co-authored-by: Yigit Gunsur Elmacioglu <102380275+YigitElma@users.noreply.github.com>

2. Changing import to use desc.backend 3. Fixing notebook issue

…maControl/DESC into ffu/quadcoil-qss-pre-commit

…e-commit

codecov · 2026-08-13T21:24:56Z

Codecov Report

❌ Patch coverage is 64.97696% with 152 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.94%. Comparing base (ef795c5) to head (8aa5ac6).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
desc/objectives/_quadcoil.py	69.26%	71 Missing ⚠️
desc/objectives/_quadcoil_utils.py	67.05%	57 Missing ⚠️
desc/geometry/curve.py	8.69%	21 Missing ⚠️
desc/coils.py	40.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2110      +/-   ##
==========================================
+ Coverage   84.50%   93.94%   +9.44%     
==========================================
  Files         101      103       +2     
  Lines       28953    29386     +433     
==========================================
+ Hits        24466    27607    +3141     
+ Misses       4487     1779    -2708

Files with missing lines	Coverage Δ
desc/io/optimizable_io.py	`87.05% <100.00%> (+0.58%)`	⬆️
desc/objectives/__init__.py	`100.00% <100.00%> (ø)`
desc/coils.py	`97.09% <40.00%> (+6.99%)`	⬆️
desc/geometry/curve.py	`93.56% <8.69%> (+13.97%)`	⬆️
desc/objectives/_quadcoil_utils.py	`67.05% <67.05%> (ø)`
desc/objectives/_quadcoil.py	`69.26% <69.26%> (ø)`

... and 67 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

YigitElma · 2026-08-13T21:55:01Z

I made some small changes to fix the failing test and fixed a couple of bugs (for example, classmethods expect cls as the first argument). In the notebook, I added a helper function for plotting, I think you can use it instead of duplicated code (I just added the helper, but didn't change the code to use it yet). Also, it looks like the notebook is currently trying to use 127GB of memory which is not possible to run on CI. I added jac_chunk_size=1 to QuadcoilProxy objective, but we may need to reduce the resolution or something else to keep it short. For CI purposes, we want notebooks to run in around 10 minutes.

One additional question for other devs: do we want this in the desc/objectives module or desc/external module? @dpanici @f0uriest @ddudt

lankef and others added 30 commits April 4, 2025 12:23

initial commit to add a quadcoil-based objective. A direct interface …

e930a2e

…also coming soon.

initial commit of the QUADCOIL objective, tweaking 2 control flows in…

69a5e87

… optimizable_io.py and objective_funs.py to avoid error for static, empty tuple attributes and _objectives with self.coordinates == \'\'

still debugging instability

74892d8

Improving printing

395d8f9

Initial commit about single-stage

6426650

fixing init

925e19e

Updating QuadcoilObject

773651e

Completing QUADCOIL single-stage interface, testing

c36d534

Renaming and minor bug fixes

dc6a65e

Fixes for static attrs

45e88d8

Fixes for static attrs

f243182

Merge remote-tracking branch 'origin/master' into ffu/quadcoil

59ec216

Merge remote-tracking branch 'origin/master' into ffu/quadcoil

a7c368f

Merge remote-tracking branch 'origin/master' into ffu/quadcoil

87c86e4

Testing for static argument error

7e6d350

Fixing quadcoil

6507199

Adding simsopt curve conversion

c4300f5

Accommodating external fields in QuadcoilProxy

c4754d4

Minor changes

25e96af

QuadcoilField first working. Adding external coil support.

3afd240

Fixing single stage. Re-organizing quadcoil-related codes to reduce c…

e47c443

…opy and pasting.

minor fix, registering quadcoilfield.

8d8de33

Fixing data_index for quadcoilfield

b96e3db

Adding conversion from QuadcoilProxy to QuadcoilField for cutting

18e82c0

Minor update. Attempting to write a quadcoil proxy-> quadcoilfield co…

a5455f8

…nversion, but it's not working because quadcoilproxy does not directly store the input dictionary, and desc static dict cannot contain strings (?)

Minor correction, fixing coil conversion to follow simsopt updates

1d0ff07

Merge remote-tracking branch 'origin/master' into ffu/quadcoil

0ecd9f1

Moving _set_tight_layout from line 988 to 973 to avoid RuntimeError…

b6fea15

…: Colorbar layout of new layout engine not compatible with old engine, and a colorbar has been created. Engine not changed.

removing quadcoil single-stage files that are immature and not ready …

8fa750d

…for merging into main

removing quadcoil single-stage files that are immature and not ready …

7b576d1

…for merging into main

Notebook update to switch from simsopt plotting to desc plotting.

eaff201

YigitElma reviewed Apr 24, 2026

View reviewed changes

lankef and others added 5 commits May 2, 2026 13:22

Update desc/geometry/curve.py

90c862c

Co-authored-by: Yigit Gunsur Elmacioglu <102380275+YigitElma@users.noreply.github.com>

formatting docstring

9871de1

Merge branch 'ffu/quadcoil-qss-pre-commit' of https://github.com/Plas…

887dfc0

…maControl/DESC into ffu/quadcoil-qss-pre-commit

formatting warnings with f-string to improve readability. Formatting …

4942d9d

…dict popping with defaults using pop(default=**) to improve readability

moving static_attrs definitions to right after the docstring.

d947a56

lankef and others added 17 commits August 12, 2026 14:46

Update desc/objectives/_quadcoil.py

57b26b1

Co-authored-by: Yigit Gunsur Elmacioglu <102380275+YigitElma@users.noreply.github.com>

1. Removing redundant static attrs in _quadcoil.py

17c83ed

2. Changing import to use desc.backend 3. Fixing notebook issue

Merge branch 'ffu/quadcoil-qss-pre-commit' of https://github.com/Plas…

af2e155

…maControl/DESC into ffu/quadcoil-qss-pre-commit

*may not work* removing a hacky fix in objective_funs.py

206b7c5

Fixing a KeyError

3bc0564

Merge branch 'master' into ffu/quadcoil-qss-pre-commit

fbc66b5

Removing useless cells

926b124

Merge branch 'master' into ffu/quadcoil-qss-pre-commit

41d6503

Fixing doc issues

f8fe00e

Merge branch 'ffu/quadcoil-qss-pre-commit' of https://github.com/Plas…

66e0d33

…maControl/DESC into ffu/quadcoil-qss-pre-commit

revert plotting.py changes

54744c8

comment gpu line

d449102

Fixing 2 unit test issues

cb09b43

Merge branch 'ffu/quadcoil-qss-pre-commit' of https://github.com/Plas…

70c041d

…maControl/DESC into ffu/quadcoil-qss-pre-commit

fix unit tests, clean-up

582e246

Merge remote-tracking branch 'origin/master' into ffu/quadcoil-qss-pr…

c9ee558

…e-commit

mostly cosmetic clean-ups and comments

17c9a7f

Reducing notebook memory usage by reducing equilibrium resolution

8aa5ac6

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