Add an extra test for nested submodels

[penelopeysm]

Probably a good idea to check ...

[github-actions]

Benchmark Report

• this PR's head: 8db36dcb35e0d14b41efb9a535d184a3c80b146e
• base branch: c1ec928ac9e9ee977247e8ec6056f69f9e4ee2c8

Computer Information

Julia Version 1.11.9
Commit 53a02c0720c (2026-02-06 00:27 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 4 × AMD EPYC 7763 64-Core Processor
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, znver3)
Threads: 1 default, 0 interactive, 1 GC (on 4 virtual cores)

Benchmark Results

┌───────────────────────┬───────┬─────────────┬────────┬───────────────────────────────┬────────────────────────────┬─────────────────────────────────┐
│                       │       │             │        │       t(eval) / t(ref)        │     t(grad) / t(eval)      │        t(grad) / t(ref)         │
│                       │       │             │        │ ─────────┬──────────┬──────── │ ───────┬─────────┬──────── │ ──────────┬───────────┬──────── │
│                 Model │   Dim │  AD Backend │ Linked │     base │  this PR │ speedup │   base │ this PR │ speedup │      base │   this PR │ speedup │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│               Dynamic │    10 │    mooncake │   true │   282.29 │   281.18 │    1.00 │   7.31 │    6.33 │    1.16 │   2064.94 │   1779.98 │    1.16 │
│                   LDA │    12 │ reversediff │   true │  2572.77 │  2392.90 │    1.08 │   2.04 │    2.11 │    0.96 │   5238.52 │   5059.65 │    1.04 │
│   Loop univariate 10k │ 10000 │    mooncake │   true │ 31099.16 │ 27692.66 │    1.12 │   6.80 │    7.98 │    0.85 │ 211392.92 │ 220948.60 │    0.96 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│    Loop univariate 1k │  1000 │    mooncake │   true │  3157.94 │  3776.19 │    0.84 │   6.25 │    5.92 │    1.06 │  19746.61 │  22345.14 │    0.88 │
│      Multivariate 10k │ 10000 │    mooncake │   true │ 31890.52 │ 32639.99 │    0.98 │   9.98 │    8.74 │    1.14 │ 318414.03 │ 285231.39 │    1.12 │
│       Multivariate 1k │  1000 │    mooncake │   true │  3496.79 │  3590.82 │    0.97 │   9.19 │    8.31 │    1.11 │  32145.52 │  29841.29 │    1.08 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│ Simple assume observe │     1 │ forwarddiff │  false │     0.88 │     0.83 │    1.06 │  10.52 │   11.21 │    0.94 │      9.24 │      9.32 │    0.99 │
│           Smorgasbord │   201 │ forwarddiff │  false │   972.84 │   871.38 │    1.12 │  70.43 │   79.39 │    0.89 │  68518.54 │  69179.57 │    0.99 │
│           Smorgasbord │   201 │      enzyme │   true │  1300.16 │  1216.10 │    1.07 │   4.87 │    4.45 │    1.09 │   6327.70 │   5416.23 │    1.17 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│           Smorgasbord │   201 │ forwarddiff │   true │  1298.11 │  1211.90 │    1.07 │  68.72 │   68.58 │    1.00 │  89210.43 │  83112.91 │    1.07 │
│           Smorgasbord │   201 │    mooncake │   true │  1304.15 │  1235.78 │    1.06 │   4.64 │    4.56 │    1.02 │   6057.58 │   5638.20 │    1.07 │
│           Smorgasbord │   201 │ reversediff │   true │  1294.62 │  1201.15 │    1.08 │ 128.75 │  127.76 │    1.01 │ 166687.98 │ 153456.75 │    1.09 │
├───────────────────────┼───────┼─────────────┼────────┼──────────┼──────────┼─────────┼────────┼─────────┼─────────┼───────────┼───────────┼─────────┤
│              Submodel │     1 │    mooncake │   true │     0.88 │     0.87 │    1.01 │  26.83 │   27.99 │    0.96 │     23.61 │     24.34 │    0.97 │
└───────────────────────┴───────┴─────────────┴────────┴──────────┴──────────┴─────────┴────────┴─────────┴─────────┴───────────┴───────────┴─────────┘

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.59%. Comparing base (c1ec928) to head (8db36dc).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1346   +/-   ##
=======================================
  Coverage   78.59%   78.59%           
=======================================
  Files          50       50           
  Lines        3626     3626           
=======================================
  Hits         2850     2850           
  Misses        776      776           

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