Elamur Groupantsmlab-builtins-table-missing-windows
The groupant beside mlab/src/builtins/table.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | partial bounded parent evidence | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
window_coordinates | window_coordinates | partial source derived model | window_coordinates |
empty_boundary | empty_boundary | partial source derived model | empty_boundary |
branch_relation | branch_relation | partial source derived model | branch_relation |
resource_cost | resource_cost | partial source derived model | resource_cost |
Model text
descriptant
mlab-builtins-table-missing-windows
ismissing maps numeric NaN except char to logical mask; rmmissing removes missing vector cells or whole matrix/table rows. moving scalar even k uses kb=k/2,kf=k/2-1; endpoints shrink, pair widths max0 then cast.
Epoch 2026-10-31: isolated source-bound fragment over bytes [22422,26346); includes no claim beyond this relation. Source hash f1b0959092cfcdd3cbd171a48d252ce4c1e652b1e56ed030c160e7667d8cbb54.
approximant
missing-windows: forward relation
ismissing maps numeric NaN except char to logical mask; rmmissing removes missing vector cells or whole matrix/table rows. moving scalar even k uses kb=k/2,kf=k/2-1; endpoints shrink, pair widths max0 then cast.
Domain: Well-shaped values and finite practical windows; effects delegated to it.fs. Physical filesystem not exercised.
Executable surrogate gap: no measured cheaper implementation with a useful scoped metric is supplied. Categorical/error/effect relations are exact obligations, not percent losses. Future numeric caps only1/2/5/10%.
invariant
missing-windows: invariant and cost
Output shape retained for numeric moving; row vectors traverse horizontally, matrices down columns.
No loop executes for zero rows; extreme widths may overflow i+kf; finite practical widths only.
Scope-specific cost: Missing scans O(nw); moving mean/sum/min/max O(nwlen), median O(nwlen log wlen); O(n) column scratch plus output.
models
behavior_complement
NaN removal loses original positions. movmedian sorts with partial_cmp unwrap and can panic on NaN; no universal NaN propagation guarantee across window methods.
reverse_reconstruction
Removed rows admit arbitrary inserted missing rows; a moving sum admits kernel nullspaces and boundary constraints, not unique pointwise inversion.
window_coordinates
Output shape retained for numeric moving; row vectors traverse horizontally, matrices down columns.
empty_boundary
No loop executes for zero rows; extreme widths may overflow i+kf; finite practical widths only.
branch_relation
ismissing maps numeric NaN except char to logical mask; rmmissing removes missing vector cells or whole matrix/table rows. moving scalar even k uses kb=k/2,kf=k/2-1; endpoints shrink, pair widths max0 then cast.
resource_cost
Missing scans O(nw); moving mean/sum/min/max O(nwlen), median O(nwlen log wlen); O(n) column scratch plus output.
tests
Evidence boundary
See ../tests.md for the actual selected source test and mutant. These tests sample the file, not every fragment branch. NaN removal loses original positions. movmedian sorts with partial_cmp unwrap and can panic on NaN; no universal NaN propagation guarantee across window methods. Other branches here are source-derived and unexecuted unless the parent test explicitly calls them.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/mlab/src/builtins/table.rs.groupant/missing-windows.groupant/