# Status Snapshot
Last updated: 2026-04-15
## Summary
`ndatafusion` is now well past the initial v1 target.
Current validated surface:
1. `147` scalar UDFs registered through `register_all`
2. `4` aggregate UDFs registered through `register_all`
3. `1` table function, `unpack_struct`, registered through `register_all_session`
4. real-valued support across canonical `Float32` and `Float64` dense vector, dense matrix,
sparse CSR, fixed-shape tensor, variable-shape tensor, matrix-equation, statistics, grouped
aggregate, and tensor-decomposition workflows
5. complex-valued support across canonical `ndarrow.complex64` dense vector, dense matrix,
complex PCA, fixed-shape tensor, and variable-shape tensor workflows
6. named arguments, aliases, custom scalar coercion, programmatic `documentation()`, per-UDF
simplify hooks, retractable aggregates, and a table-function entry point for struct unpacking
Validation on the current tree:
1. `just checks` passes
2. line coverage is `90.01%`
3. `cargo doc --no-default-features --no-deps` passes and `just docsrs-check` passes
4. `cargo package --allow-dirty --no-default-features` passes
5. `cargo publish --dry-run --allow-dirty --no-default-features` passes
## Current Surface
Implemented and covered today:
1. constructor UDFs for canonical vector, matrix, fixed-shape tensor, variable-shape tensor, and
CSR sparse-batch contracts
2. dense vector, dense matrix, decomposition, direct-solver, spectral, matrix-function, and
matrix-equation UDFs across the admitted real-valued surface
3. complex vector, matrix, complex PCA, complex tensor, and complex spectral/matrix-function UDFs
4. sparse factorization and preconditioner UDFs using explicit struct-valued state contracts
5. named-function differentiation UDFs: `jacobian`, `jacobian_central`, `gradient`, `hessian`
6. named-function complex optimization UDFs
7. tensor decomposition and tensor-train UDFs
8. grouped aggregate UDFs for covariance, correlation, PCA fit, and linear regression fit
9. ordered window use of the current aggregate wave through retractable aggregate state
10. `unpack_struct` as a generic one-row table-function bridge for struct-valued scalar results
## Release Posture
`ndatafusion` is ready for continued git consumption and first crates.io publication.
Current dependency posture:
1. crates.io `datafusion 53.0.0` aligns with Arrow 58, `ndarrow 0.0.3`, and `nabled 0.0.7`
2. publish validation passes on the current tree
3. the tagged release workflow can publish to crates.io when `CARGO_REGISTRY_TOKEN` is configured
## Next Directions
The remaining work is no longer foundational implementation. It is planning and selective
expansion work:
1. cut the first crates.io release from the current validated surface
2. broader planner hooks beyond `simplify`, only where they materially help optimization
3. custom expression planning for SQL forms that do not fit ordinary scalar, aggregate, or table
functions
4. richer table-function surfaces only where a relation-shaped contract is genuinely better than a
struct-valued scalar result
5. optional dedicated `WindowUDF` surfaces only if retractable aggregates become insufficient