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mdl: xmutil comparison may still expect dropped C-LEARN flow subscripts #570
Description
The MDL importer deliberately differs from xmutil on one C-LEARN idiom, and the xmutil comparison test may still expect xmutil's answer.
In C-LEARN, a one-dimensional stock takes a flow pinned to one element of a two-dimensional variable:
Heat in Atmosphere and Upper Ocean[scenario] = INTEG(... - Heat Transfer[scenario, layer1], ...)
xmutil drops the layer1 subscript; our importer keeps it, which is correct and is needed for C-LEARN to simulate.
The test that compared our importer's output with xmutil's on C-LEARN (test_clearn_equivalence in mdl_equivalence.rs) was ignored and behind the xmutil feature, so nobody ran it, and its recorded count of known differences may no longer hold.
Status
xmutil and its comparison tests have since been removed from the repo (#1080), so there is nothing left to re-check.
C-LEARN is held to Vensim's own run (Ref.vdf) by simulates_clearn instead.
Activity
[-]engine: B2-A intentional flow-subscript divergence (eae79426) needs xmutil-gated mdl_equivalence/test_clearn_equivalence verified-or-updated before B2 PR (same class as #512)[/-][+]mdl: xmutil comparison may still expect dropped C-LEARN flow subscripts[/+]bpowers commentedon Oct 12, 2026
Closing: already fixed on main.
Obsolete: xmutil and
tests/mdl_equivalence.rs(includingtest_clearn_equivalence) were deleted in ea8367a (#1080), so no test expects xmutil's dropped subscript. C-LEARN is held to Vensim's Ref.vdf bysimulates_clearn(tests/integration/simulate.rs:4010), and the kept subscript is pinned in mdl/convert/stocks.rs:1303.