VSAR: VSA-grounded Reasoning

VSAR (VSAX Reasoner) is a VSA-grounded reasoning system that combines Datalog-style logic programming with approximate vector matching. Built on VSAX library for GPU-accelerated hypervector operations, VSAR enables fast approximate reasoning over large knowledge bases with explainable results.

Think of it as: "Datalog meets vector similarity search" - a foundation for approximate deductive reasoning at scale.

🌟 Key Features

Deductive Reasoning

• Horn clause rules - Full support for head :- body1, body2, ... syntax
• Forward chaining - Iterative rule application with fixpoint detection
• Transitive closure - Multi-hop inference (arbitrary depth)
• Semi-naive evaluation - Optimized chaining that avoids redundant work

Approximate Matching

• VSA-based similarity - Fuzzy matching with confidence scores instead of exact symbolic matching
• Graceful degradation - Works with noisy data and typos
• Beam search joins - Prevents combinatorial explosion in multi-body rules
• Novelty detection - Prevents duplicate derivations via similarity threshold

Performance & Scale

• Fast approximate querying - Query 10^6+ facts with subsymbolic retrieval
• Vectorized operations - GPU-ready via JAX backend
• Predicate partitioning - Efficient KB organization
• HDF5 persistence - Save and load knowledge bases

Developer Experience

• VSAR IDE - Complete visual development environment (like DrRacket for VSAR)
• VSARL language - Declarative syntax for facts, queries, and rules
• Interactive REPL - Load files and query interactively
• CLI interface - Simple commands for ingestion, querying, and export
• Full traceability - Explanation DAG for debugging and transparency
• Comprehensive testing - 392 tests with 97.56% coverage

📦 Installation

From PyPI (Recommended)

pip install vsar

# Verify installation
vsar --help

Development Install

# Install uv (fast Python package installer)
pip install uv

# Clone and install
git clone https://github.com/vasanthsarathy/vsar.git
cd vsar
uv sync

# For development, use uv run
uv run vsar --help

🚀 Quick Start

Example 1: Basic Facts and Queries

Create family.vsar:

@model FHRR(dim=1024, seed=42);

fact parent(alice, bob).
fact parent(bob, carol).
fact parent(carol, dave).

query parent(alice, X)?
query parent(X, carol)?

Run it:

vsar run family.vsar

Output:

Inserted 3 facts

┌─────────────────────────┐
│ Query: parent(alice, X) │
├────────┬────────────────┤
│ Entity │ Score          │
├────────┼────────────────┤
│ bob    │ 0.9234         │
└────────┴────────────────┘

Example 2: Reasoning with Rules (Phase 2)

Create reasoning.vsar:

@model FHRR(dim=1024, seed=42);
@beam(width=50);
@novelty(threshold=0.95);

// Base facts: Parent relationships
fact parent(alice, bob).
fact parent(bob, carol).
fact parent(carol, dave).

// Rule: Derive grandparent relationship
rule grandparent(X, Z) :- parent(X, Y), parent(Y, Z).

// Rule: Transitive closure for ancestors
rule ancestor(X, Y) :- parent(X, Y).
rule ancestor(X, Z) :- parent(X, Y), ancestor(Y, Z).

// Queries
query grandparent(alice, X)?
query ancestor(alice, X)?

Run it:

vsar run reasoning.vsar

Output:

Inserted 3 facts

Applied 3 rules in 2 iterations
Derived 5 new facts
Fixpoint reached: true

┌──────────────────────────────┐
│ Query: grandparent(alice, X) │
├────────┬─────────────────────┤
│ Entity │ Score               │
├────────┼─────────────────────┤
│ carol  │ 0.8456              │
└────────┴─────────────────────┘

┌───────────────────────────┐
│ Query: ancestor(alice, X) │
├────────┬──────────────────┤
│ Entity │ Score            │
├────────┼──────────────────┤
│ bob    │ 0.9234           │
│ carol  │ 0.8876           │
│ dave   │ 0.8123           │
└────────┴──────────────────┘

Example 3: Interactive REPL

vsar repl

Example session:

VSAR Interactive REPL
Type 'help' for commands, 'exit' to quit

> load family.vsar
Loaded family.vsar
Inserted 3 facts

> query parent(alice, X)?
┌─────────────────────────┐
│ Query: parent(alice, X) │
├────────┬────────────────┤
│ Entity │ Score          │
├────────┼────────────────┤
│ bob    │ 0.9234         │
└────────┴────────────────┘

> stats
Knowledge Base Statistics
Total Facts: 3
Predicates: parent (3 facts)

> exit
Goodbye!

🎨 VSAR IDE - Interactive Development Environment

VSAR includes a complete visual IDE (similar to DrRacket) for an enhanced development experience.

Launch the IDE

vsar-ide

IDE Features

Visual Interface:

• Split-pane layout - Editor (left) + Console (right)
• Syntax highlighting - Real-time color-coding for VSARL
  • Keywords (fact, rule, query) in blue
  • Directives (@model, @beam) in purple
  • Comments (//, /* */) in gray
  • Variables (uppercase) in orange
  • Predicates (lowercase) in black

Development Workflow:

• File operations - New (Ctrl+N), Open (Ctrl+O), Save (Ctrl+S), Save As (Ctrl+Shift+S)
• Run programs - Press F5 to execute entire programs
• Interactive queries - Ctrl+Q to run queries on-demand
• KB statistics - View facts and predicate breakdowns
• Color-coded output - Errors, successes, and warnings clearly marked

Quick Start with IDE:

1. Launch vsar-ide
2. Create a new file or open an example
3. Write your VSAR program
4. Press F5 to run
5. Use Ctrl+Q for interactive queries

Perfect for:

• Learning VSAR and experimenting
• Developing and testing programs
• Debugging with visual feedback
• Teaching and demonstrations

📚 Documentation

Tutorials

• Getting Started - Your first VSAR program
• Tutorial: Family Tree Reasoning - Multi-hop inference
• Tutorial: Organizational Hierarchies - Manager chains
• Tutorial: Knowledge Graphs - Multi-relation reasoning

User Guides

• VSARL Language Reference - Complete syntax guide
• CLI Commands - Command-line interface
• Python API - Programmatic usage
• Architecture Overview - System design

Reference

• API Reference - Complete API documentation
• Examples Directory - 6 example programs with explanations
• PROGRESS.md - Current capabilities and limitations
• CHANGELOG.md - Version history

🎯 What Can VSAR Do?

✅ Currently Supported (Phase 0-2)

Deductive Reasoning:

• ✅ Ground facts insertion and querying
• ✅ Horn clause rules (head :- body1, body2, ...)
• ✅ Forward chaining with fixpoint detection
• ✅ Multi-hop inference (transitive closure)
• ✅ Recursive rules (arbitrary depth)
• ✅ Multiple interacting rules
• ✅ Semi-naive evaluation optimization

Approximate Reasoning:

• ✅ Similarity-based retrieval (fuzzy matching)
• ✅ Confidence scores for all results
• ✅ Graceful degradation under noise
• ✅ Top-k ranked results

Performance:

• ✅ Beam search joins (controls combinatorial explosion)
• ✅ Novelty detection (prevents duplicates)
• ✅ Vectorized operations (GPU-ready)
• ✅ Predicate partitioning

Developer Experience:

• ✅ Declarative VSARL language
• ✅ Interactive REPL
• ✅ CLI interface
• ✅ Full traceability and provenance
• ✅ HDF5 persistence

⏳ Limitations (Planned for Phase 3+)

• ⏳ Single-variable queries only - parent(alice, ?) works, parent(?, ?) doesn't yet
• ⏳ No negation - Cannot express not enemy(X, Y) or negation-as-failure
• ⏳ No aggregation - Cannot count, sum, max, etc.
• ⏳ Forward chaining only - No backward chaining or goal-directed search
• ⏳ No magic sets - Cannot optimize query-driven derivation

See PROGRESS.md for detailed capability analysis and roadmap.

🏗️ Architecture

VSAR uses a layered architecture:

┌─────────────────────────────────────────┐
│         VSARL Language & CLI            │  (Phase 1)
│  Parser, AST, Engine, Trace, CLI        │
├─────────────────────────────────────────┤
│       Semantic Layer (Reasoning)        │  (Phase 2)
│  Substitution, Joins, Chaining, Rules   │
├─────────────────────────────────────────┤
│     Retrieval & Query Execution         │  (Phase 0)
│  Unbinding, Cleanup, Top-k Retrieval    │
├─────────────────────────────────────────┤
│        Knowledge Base (Storage)         │  (Phase 0)
│  Predicate Bundles, HDF5 Persistence    │
├─────────────────────────────────────────┤
│      Encoding (Role-Filler Binding)     │  (Phase 0)
│  Atom Encoding, Role Vector Management  │
├─────────────────────────────────────────┤
│    Symbol Registry (Typed Spaces)       │  (Phase 0)
│  E, R, A, C, T, S spaces + Basis Mgmt   │
├─────────────────────────────────────────┤
│    VSA Kernel (Hypervector Algebra)    │  (Phase 0)
│      FHRR, MAP Backends via VSAX        │
└─────────────────────────────────────────┘

Key Principles:

• Approximate is explicit - Every result has a similarity score
• Modular semantics - Clean separation of concerns
• Bounded inference - Beam widths, hop limits, novelty thresholds
• Typed symbol spaces - Entities (E), Relations (R), Attributes (A), etc.

📖 VSARL Language

Facts

fact parent(alice, bob).
fact parent(bob, carol).
fact lives_in(alice, boston).
fact transfer(alice, bob, money).   // Ternary fact
fact person(alice).                  // Unary fact

Rules (Phase 2)

// Grandparent: X is grandparent of Z if X is parent of Y and Y is parent of Z
rule grandparent(X, Z) :- parent(X, Y), parent(Y, Z).

// Ancestor: Base case
rule ancestor(X, Y) :- parent(X, Y).

// Ancestor: Recursive case (transitive closure)
rule ancestor(X, Z) :- parent(X, Y), ancestor(Y, Z).

// Sibling: Share same parent
rule sibling(X, Y) :- parent(Z, X), parent(Z, Y).

Queries

query parent(alice, X)?         // Find children of alice
query parent(X, carol)?         // Find parents of carol
query grandparent(alice, X)?    // Find grandchildren of alice (via rules)
query ancestor(alice, X)?       // Find all descendants (transitive)

Directives

// Model configuration
@model FHRR(dim=1024, seed=42);    // FHRR backend, 1024 dimensions
@model MAP(dim=512, seed=100);     // MAP backend (alternative)

// Retrieval parameters
@threshold 0.22;                   // Similarity threshold
@beam(width=50);                   // Beam width for joins
@novelty(threshold=0.95);          // Novelty detection threshold

Comments

// Single-line comment

/* Multi-line
   comment */

🔧 CLI Reference

Run Programs

# Run a VSAR program
vsar run program.vsar

# Limit results per query
vsar run program.vsar --k 10

# JSON output (for scripting)
vsar run program.vsar --json

# Show trace DAG
vsar run program.vsar --trace

Ingest Facts

# From CSV (predicate in first column)
vsar ingest facts.csv --kb family.h5

# From CSV (specify predicate)
vsar ingest parents.csv --predicate parent --kb family.h5

# From JSONL
vsar ingest facts.jsonl --kb family.h5

Export & Inspect

# Export KB to JSON
vsar export family.h5 --format json --output facts.json

# Export to JSONL
vsar export family.h5 --format jsonl --output facts.jsonl

# Inspect KB statistics
vsar inspect family.h5

Interactive REPL

# Start interactive session
vsar repl

# Available commands:
# - load <file>      Load a VSAR program
# - query <query>    Execute a query
# - stats            Show KB statistics
# - help             Show help
# - exit             Exit REPL

🐍 Python API

High-Level API (Recommended)

from vsar.language.ast import Directive, Fact, Query, Rule, Atom
from vsar.semantics.engine import VSAREngine

# Configure engine
directives = [
    Directive(name="model", params={"type": "FHRR", "dim": 1024, "seed": 42}),
    Directive(name="beam", params={"width": 50}),
    Directive(name="novelty", params={"threshold": 0.95}),
]
engine = VSAREngine(directives)

# Insert facts
engine.insert_fact(Fact(predicate="parent", args=["alice", "bob"]))
engine.insert_fact(Fact(predicate="parent", args=["bob", "carol"]))

# Define rules
rules = [
    Rule(
        head=Atom(predicate="grandparent", args=["X", "Z"]),
        body=[
            Atom(predicate="parent", args=["X", "Y"]),
            Atom(predicate="parent", args=["Y", "Z"]),
        ],
    )
]

# Query with automatic rule application
query = Query(predicate="grandparent", args=["alice", None])
result = engine.query(query, rules=rules, k=10)

for entity, score in result.results:
    print(f"{entity}: {score:.4f}")

# Inspect trace
trace = engine.trace.get_dag()
for event in trace:
    print(f"{event.type}: {event.payload}")

# Get KB statistics
stats = engine.stats()
print(f"Total facts: {stats['total_facts']}")

# Save/load KB
engine.save_kb("family.h5")
engine.load_kb("family.h5")

Forward Chaining

from vsar.semantics.chaining import apply_rules

# Apply rules with forward chaining
result = apply_rules(
    engine,
    rules,
    max_iterations=100,
    k=10,
    semi_naive=True  # Use semi-naive evaluation (faster)
)

print(f"Iterations: {result.iterations}")
print(f"Total derived: {result.total_derived}")
print(f"Fixpoint reached: {result.fixpoint_reached}")

Loading from Files

from vsar.language.loader import ProgramLoader

# Load VSAR program
loader = ProgramLoader()
program = loader.load_file("examples/02_family_tree.vsar")

# Create engine from program directives
engine = VSAREngine(program.directives)

# Insert all facts
for fact in program.facts:
    engine.insert_fact(fact)

# Execute all queries with rules
for query in program.queries:
    result = engine.query(query, rules=program.rules, k=10)
    print(f"Query: {query.predicate}({', '.join(str(a) for a in query.args)})")
    print(f"Results: {result.results}")

📊 Performance

Approximate query performance (Phase 2, with rules):

Facts	Query Time	Chaining Time (10 rules)
10^3	<50ms	<200ms
10^4	<100ms	<500ms
10^5	<300ms	<2s
10^6	<800ms	<10s

Measured on AMD EPYC 7742 CPU with dim=1024, beam=50

Memory usage:

• Base: ~50MB (dim=1024)
• Per 1000 facts: ~5MB
• Scales linearly with fact count and dimensionality

🧪 Testing

# Run all tests
pytest

# Run with coverage
pytest --cov=vsar --cov-report=html

# Run specific test suites
pytest tests/unit/              # Unit tests
pytest tests/integration/       # Integration tests
pytest tests/integration/test_e2e_phase2.py  # End-to-end tests

Test Statistics:

• 392 tests (all passing, 4 skipped)
• 97.56% coverage
• Unit tests: 370
• Integration tests: 22
• End-to-end tests: 5

🗺️ Project Status & Roadmap

✅ Phase 0: Foundation (Complete)

• VSA kernel (FHRR, MAP backends)
• Symbol registry and encoding
• KB storage with predicate partitioning
• Basic retrieval with similarity search
• HDF5 persistence

✅ Phase 1: Ground KB + Queries (Complete)

• VSARL language parser
• Facts ingestion (CSV/JSONL/VSAR)
• Single-variable queries
• CLI interface and REPL
• Trace collection

✅ Phase 2: Horn Rules + Chaining (Complete)

• Horn clause rules
• Variable substitution and unification
• Beam search joins
• Forward chaining with fixpoint detection
• Semi-naive evaluation
• Novelty detection
• Query with automatic rule application

🔜 Phase 3: Advanced Features (Planned)

• Multi-variable queries (parent(?, ?)?)
• Stratified negation
• Aggregation (count, sum, max)
• Backward chaining
• Magic sets optimization

🔜 Phase 4: Scale & Performance (Planned)

• Incremental maintenance
• Query planning and optimization
• Parallel execution
• GPU acceleration

See PROGRESS.md for detailed status and comparison to other reasoners.

💡 Use Cases

Best suited for:

1. Knowledge graph reasoning with noise tolerance
2. Transitive closure queries (org hierarchies, supply chains)
3. Multi-hop reasoning (family trees, social networks)
4. Explainable AI (need provenance and similarity scores)
5. Large-scale approximate reasoning (vectorized operations)

Not yet suitable for:

1. Complex logical puzzles requiring negation
2. Planning problems (need backward chaining)
3. Ontology reasoning (need DL features)
4. Answer set programming tasks

🤝 Contributing

Contributions welcome! Please see CONTRIBUTING.md for guidelines.

Development setup:

# Clone repo
git clone https://github.com/vasanthsarathy/vsar.git
cd vsar

# Install with dev dependencies
uv sync --all-groups

# Run tests
uv run pytest

# Format code
uv run black .
uv run ruff check . --fix

# Type check
uv run mypy src/vsar

📜 License

MIT License - see LICENSE for details.

📚 Citation

If you use VSAR in your research, please cite:

@software{vsar2025,
  title = {VSAR: VSA-grounded Reasoning},
  author = {Sarathy, Vasanth},
  year = {2025},
  url = {https://github.com/vasanthsarathy/vsar},
  version = {0.3.0}
}

🙏 Acknowledgments

• Built on VSAX for VSA operations
• Inspired by Datalog, Prolog, and logic programming systems
• Uses Lark for parsing
• CLI powered by Typer and Rich
• Testing with pytest

📞 Support

• Documentation: docs/
• Examples: examples/
• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Made with ❤️ for approximate reasoning at scale.