Equilibrium - BUGFIX - Select the rectangular profiles_2d by grid_type in read_imas

[calin1989]

Release note

• Audience: users
• Numerical impact: none (harness @ 4681a3c)
• Migration: none

GPEC can now read IMAS equilibria that store more than one 2D map, such as those from TEQUILA. read_imas previously always took the first profiles_2d entry, which for TEQUILA is not the rectangular R,Z grid.

Regression report

Regression Report: diiid_n1
=================================================================================================
Ref 1: 6553fe205  @ 6553fe205 (2026-10-07)
       env: julia 1.12.6, arm64-apple-darwin24.0.0, manifest ece8f5d1 (pinned), 4 threads/4 BLAS
Ref 2: 4681a3c06  @ 4681a3c06 (2026-10-07)
       env: julia 1.12.6, arm64-apple-darwin24.0.0, manifest ece8f5d1 (pinned), 4 threads/4 BLAS
-------------------------------------------------------------------------------------------------
Quantity                                      6553fe205        4681a3c06        Diff       Status
-------------------------------------------------------------------------------------------------
total energy Re(et[1])                        8.013943e-01     8.013943e-01     0.0e+00    OK
total energy Im(et[1])                        1.233500e-04     1.233500e-04     0.0e+00    OK
plasma energy Re(ep[1])                       -1.348114e+00    -1.348114e+00    0.0e+00    OK
vacuum energy Re(ev[1])                       2.149508e+00     2.149508e+00     0.0e+00    OK
vacuum matrix min eigenvalue                  1.873975e-01     1.873975e-01     0.0e+00    OK
plasma energy (all)                           [35 elem]        [35 elem]        0.0e+00    OK
vacuum energy (all)                           [35 elem]        [35 elem]        0.0e+00    OK
total energy (all)                            [35 elem]        [35 elem]        0.0e+00    OK
ODE steps (saved)                             1449             1449             0.0e+00    OK
ODE steps (total)                             1444             1444             0.0e+00    OK
q0                                            1.204212e+00     1.204212e+00     0.0e+00    OK
q95                                           4.781723e+00     4.781723e+00     0.0e+00    OK
beta_t                                        1.327024e-02     1.327024e-02     0.0e+00    OK
beta_n                                        1.372511e+00     1.372511e+00     0.0e+00    OK
internal inductance li1                       8.842230e-01     8.842230e-01     0.0e+00    OK
internal inductance li2                       7.080727e-01     7.080727e-01     0.0e+00    OK
internal inductance li3                       7.304309e-01     7.304309e-01     0.0e+00    OK
poloidal beta betap1                          6.680738e-01     6.680738e-01     0.0e+00    OK
poloidal beta betap2                          5.349836e-01     5.349836e-01     0.0e+00    OK
poloidal beta betap3                          5.518763e-01     5.518763e-01     0.0e+00    OK
# singular surfaces                           5                5                0.0e+00    OK
singular psi locations                        [5 elem]         [5 elem]         0.0e+00    OK
singular q values                             [5 elem]         [5 elem]         0.0e+00    OK
current beta betaj                            4.236479e-01     4.236479e-01     0.0e+00    OK
plasma volume                                 1.829472e+01     1.829472e+01     0.0e+00    OK
plasma current                                1.152130e+00     1.152130e+00     0.0e+00    OK
mpert                                         35               35               0.0e+00    OK
npert                                         1                1                0.0e+00    OK
toroidal field bt0                            2.006573e+00     2.006573e+00     0.0e+00    OK
wall field bwall                              3.880145e-01     3.880145e-01     0.0e+00    OK
aspect ratio                                  2.845746e+00     2.845746e+00     0.0e+00    OK
elongation kappa                              1.708322e+00     1.708322e+00     0.0e+00    OK
q profile (checksum)                          ed7c21fd61df...  ed7c21fd61df...  identical  OK
pressure profile (checksum)                   e15550827bf1...  e15550827bf1...  identical  OK
Mercier D_I profile (checksum)                5a6fcb1c3a97...  5a6fcb1c3a97...  identical  OK
resistive interchange D_R profile (checksum)  6284a4c9a75a...  6284a4c9a75a...  identical  OK
ballooning Delta' profile (checksum)          fe06936f5840...  fe06936f5840...  identical  OK
island half-widths                            [5 elem]         [5 elem]         0.0e+00    OK
Chirikov parameter                            [5 elem]         [5 elem]         0.0e+00    OK
||resonant area-weighted field||              5.207668e-04     5.207668e-04     0.0e+00    OK
dominant-coupling singular values             [3 elem]         [3 elem]         0.0e+00    OK
|forcing overlap with dominant mode|          1.422984e-04     1.422984e-04     0.0e+00    OK
|delta_nominal| of coil set 1                 N/A              N/A              N/A        N/A
||ddelta/d(shift)|| over coil sets            N/A              N/A              N/A        N/A
||ddelta/d(tilt)|| over coil sets             N/A              N/A              N/A        N/A
PE plasma energy                              3.422586e+00     3.422586e+00     0.0e+00    OK
PE vacuum energy                              3.174509e+00     3.174509e+00     0.0e+00    OK
PE surface energy                             5.841099e+00     5.841099e+00     0.0e+00    OK
PE toroidal torque                            -5.062793e-02    -5.062793e-02    0.0e+00    OK
NTV torque FGAR [N·m]                         5.332926e-01     5.332926e-01     0.0e+00    OK
NTV kinetic energy dW FGAR [J]                7.991398e-02     7.991398e-02     0.0e+00    OK
Runtime (s)                                   177.0s           170.4s                      --
||forcing b~|| (root-area-weighted)           4.683328e-04     4.683328e-04     0.0e+00    OK
resonant area-weighted field b^r              [5 elem]         [5 elem]         0.0e+00    OK
=================================================================================================
Summary: 50 unchanged, 3 missing/N/A

Notes for reviewers

read_imas now selects the rectangular profiles_2d entry with IMASdd's findfirst(:rectangular, …), as FUSE does, and stops with an error if there is none. The test mock now sets grid_type.index = 1, as real IMAS writers do.

🤖 Generated with Claude Code

[jhalpern30]

Nice work! Some requested changes before we get this merged, mainly focusing on comments. I challenge you to not use Claude to make the below changes on this PR :)

[jhalpern30]

There is no need to write an entire paragraph as a comment here (and above). Think - what is the most useful (if any) pieces of information a human should know about this code? LLMs have a tendency to flood code comments with extraneous information we've been trying to avoid, so its good practice to read through everything you propose to add and write it from a human perspective. My general rule of thumb is if you're adding more lines of comment than code (as is the case in this PR), you need to take a look again.

For example: a good comment here might be "find 2d profiles on the rectangular grid for a general input equilibrium"

[jhalpern30]

You say this section is exactly how FUSE locates the grid - can you point me to the relevant source code here?

[calin1989]

Yes, to what I understand FUSE selects the grid by type and not position. And the source code for this is src/actors/equilibrium/equilibrium_actor.jl lines 164 and 455, fresco_actor.jl line 85 and eggo_actor.jl line 132.( See equilibrium_actor.jl#L164, #L455, fresco_actor.jl#L85 and eggo_actor.jl#L132. So Claude suggested to use grid_type.index == 1 (the same identifier, since 1 => :rectangular in IMASdd) rather than that helper, because findfirst(:rectangular, …) skips entries whose grid_type is unset.

[jhalpern30]

Looking at all of these FUSE functions, it looks like they use the IMASdd helper

eqt2d = findfirst(:rectangular, eqt.profiles_2d)

is there a reason you aren't using this? It seems to be more convenient/clear.

[calin1989]

Yes it was for the mock to not fail, but we can solve this within the tests so switched to findfirst(:rectangular, eqt.profiles_2d). I added one line to the test mock (prof2d.grid_type.index = 1), because the helper skips maps without a grid type and the mock was the only input that didn't set one. Real files (EFIT.jl, FRESCO, CHEASE, TEQUILA) all set it.

[jhalpern30]

Great, thanks!

[jhalpern30]

Everything looks good now, thanks @calin1989! I will merge this in once tests finish