Elamur Groupantsmatrix-expression
The groupant beside models/matrix-expression.groupant 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 | forward |
| ast | not materialized | |
| composition | partial | composition |
| cost | symbolic source derived | cost |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | see source local evidence | checks |
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 |
layout-transport | representation_transport | partial source derived model | layout-transport |
syntax-context | context_partition | partial source derived model | syntax-context |
validation-order | failure_precedence | partial source derived model | validation-order |
effects | effect_boundary | partial source derived model | effects |
Model text
descriptant
matrix-expression: wave30
lexer space_before distinguishes [1 -2] from [1 - 2]; Caret and DotCaret are both left-folded by the parser, retaining distinct Pow and EPow tags. Interp resolves End to dimensions and dispatches index/ops/core. value column-major layout must survive index gather and core reshape; transpose permutes it. ops short-circuit logic belongs to interp/vm; core callbacks, files, RNG and timer effects cross group and remain unexecuted here.
This source-bound partial group organizes existing Mova code. Native evidence and excluded effects are recorded in source sidecars and the root wave30 report. Registration is not a universal proof or whole-system runtime claim.
model
matrix-expression
forward
text --lexer(context,space,line)--> tokens --parser(precedence,index_depth)--> AST --interp/vm caller--> column-major Value; index selects/mutates k=j*r+i; ops broadcasts or multiplies values; core creates/reshapes and delegates range/concat. Shape is part of output: vector selection, colon columnization, reshape and transpose differ.
invariant
On bounded well-formed matrices len(re)=r*c and optional im same length; transpose is a permutation, reshape retains flattened data, ordinary bounded assignment validation errors precede mutation. No universal validity from public fields, no finite arithmetic guarantee, and AST representation is distinct from evaluation.
cost
Lexing O(chars+tokens); ordinary parsing O(tokens) with speculative reparsing and unbounded nesting caveat. Matrix storage/transforms O(cells); indexing O(indices+output/growth), deletion may sort; broadcast O(output), multiplication O(mnk) or delegated faer; callbacks, allocation and effects add unbounded costs. No speed measurements.
composition
lexer space_before distinguishes [1 -2] from [1 - 2]; Caret and DotCaret are both left-folded by the parser, retaining distinct Pow and EPow tags. Interp resolves End to dimensions and dispatches index/ops/core. value column-major layout must survive index gather and core reshape; transpose permutes it. ops short-circuit logic belongs to interp/vm; core callbacks, files, RNG and timer effects cross group and remain unexecuted here.
domain
CPU synthetic bounded strings and well-formed matrices with finite modest indices/dimensions/range spans; no GPU, datasets, external API or live filesystem effects.
limitations
Source-derived relations; caller enforces valid buffers and resources. f64 NaNs, infinities, casts and zero behavior follow source branches, not mathematical ideal arithmetic. Seven tests observe specific contracts, not all source branches.
checks
- ast::wave30::representation
- lexer::wave30::context
- parser::wave30::precedence
- value::wave30::layout
- index::wave30::gather_update
- ops::wave30::arithmetic
- builtins::core::wave30::constructors
catalog
behavior-complement
Accepted bounded composition excludes erased matrix whitespace, right-associated unparenthesized powers, row-major reinterpretation, broadcast of incompatible non-singleton dimensions and successful shape-changing reshape with unequal numel. It does not exclude public malformed values, nonfinite arithmetic or core side effects.
reverse-reconstruction
For observation y, compatible antecedents are text/AST/state triples whose parse/evaluation gives y. Comments and spellings, overwritten/deleted cells, broadcast operand factorizations and reshape dimension syntax cause ambiguity. Transpose is uniquely invertible only on valid recorded Mat; reshape requires original shape; indexing fixes selected cells only.
layout-transport
Mat index k=jr+i is preserved by reshape buffers, permuted to ic+j by transpose and gathered by index; substituting row-major storage breaks all three joins.
syntax-context
Lexer preserves whitespace and newline observations; parser contextual sign boundary and index_depth transform them into Matrix/Unary/End versus subtraction/identifier branches.
validation-order
Whole lex precedes parse; index validates selected shape before growth; core reshape computes its unchecked known-dimension product before hole counting, then on bounded arithmetic checks hole count before divisibility/rank/product; error order cannot be commuted across adapters.
effects
Most value/lexer/parser paths allocate only; index mutates target after bounded checks; ops linalg may warn; core can mutate interpreter/RNG and inspect files/time or invoke callbacks. Pure helper test evidence never certifies those effects.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/models/matrix-expression.groupant/