semantica/docs/reference/semantic_extract.md

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Semantic Extract Module	Named entity recognition, relation extraction, event detection, and triplet generation.	magnifying-glass-chart

semantica.semantic_extract extracts structured information from unstructured text — the foundation of every knowledge graph in Semantica. All extractors support three modes: pattern-based (no API key), ML-based, and LLM-based.

Exported Classes

from semantica.semantic_extract import (
    # Primary extractors
    NamedEntityRecognizer,  # full NER coordinator (confidence_threshold, merge_overlapping)
    NERExtractor,           # core NER implementation used by NamedEntityRecognizer
    RelationExtractor,      # typed relationship extraction
    TripletExtractor,       # (subject, predicate, object) triplet generation
    EventDetector,          # event detection with participants and temporal context
    CoreferenceResolver,    # resolve pronouns and aliases to canonical entities
    # Data types
    Entity,                 # {id, text, type, confidence, start, end}
    Relation,               # {subject, predicate, object, confidence}
    Event,                  # {type, participants, temporal, location, confidence}
    CoreferenceChain,       # list of mentions resolving to the same entity
    # Advanced
    EntityClassifier,       # classify entity candidates by type
    CustomEntityDetector,   # pattern/dictionary-based custom entity detection
    TemporalEventProcessor, # extract temporal information from events
)

`NamedEntityRecognizer` is the high-level coordinator with confidence thresholding and overlap merging. `NERExtractor` is the lower-level implementation. For most use cases, start with `NERExtractor` for simplicity or `NamedEntityRecognizer` for fine-grained control.

What You Get

• NERExtractor / NamedEntityRecognizer — named entity recognition: Person, Organization, Location, Date, and custom types
• RelationExtractor — typed semantic relationships between entities (founded_by, located_in, etc.)
• TripletExtractor — direct (subject, predicate, object) triplet generation for RDF-ready output
• EventDetector — event detection with participants, temporal context, and confidence scores
• CoreferenceResolver — resolve "Apple" and "the company" to the same entity across a document

Quick Start

from semantica.semantic_extract import NERExtractor, RelationExtractor, TripletExtractor
from semantica.llms import Groq
import os

text = "Apple Inc. was founded by Steve Jobs in Cupertino in 1976."
llm  = Groq(model="llama-3.3-70b-versatile", api_key=os.getenv("GROQ_API_KEY"))

entities      = NERExtractor(method="llm", llm_provider=llm).extract(text)
relationships = RelationExtractor(method="llm", llm_provider=llm).extract(text, entities=entities)
triplets      = TripletExtractor(method="llm", llm_provider=llm).extract(text)

<img src="/assets/img/diagrams/extraction-pipeline.svg" alt="Semantic extraction pipeline: raw text fans into NER, Relation, and Coreference extractors, then merges into a Triplet Generator" style={{ width: '100%', borderRadius: '12px', margin: '0 0 24px' }} />

NERExtractor

from semantica.semantic_extract import NERExtractor
from semantica.llms import Groq
import os

# Pattern-based — fast, no API key, good for standard entity types
ner = NERExtractor(method="pattern")
entities = ner.extract("Apple Inc. was founded by Steve Jobs in Cupertino.")

# ML-based — higher accuracy, no API cost
ner = NERExtractor(method="ml", model="dslim/bert-large-NER")
entities = ner.extract(text)

# LLM-based — best accuracy, handles complex schemas and custom types
llm = Groq(model="llama-3.3-70b-versatile", api_key=os.getenv("GROQ_API_KEY"))
ner = NERExtractor(method="llm", llm_provider=llm, max_retries=3)
entities = ner.extract(text)

Output format:

[
    {"text": "Apple Inc.",  "type": "ORGANIZATION", "confidence": 0.98, "start": 0,  "end": 10},
    {"text": "Steve Jobs",  "type": "PERSON",       "confidence": 0.99, "start": 27, "end": 37},
    {"text": "Cupertino",   "type": "LOCATION",     "confidence": 0.97, "start": 41, "end": 50}
]

Custom Entity Types

ner = NERExtractor(
    method="pattern",
    custom_entities={
        "DRUG": ["aspirin", "ibuprofen", "metformin"],
        "GENE": ["BRCA1", "TP53", "EGFR"]
    }
)

**v0.5.0 fix:** `NERExtractor(method="llm")` no longer silently falls back to pattern extraction on custom gateways. The `response_format=json_object` parameter is now conditionally omitted for incompatible gateways, with a plain `generate()` + JSON parsing fallback applied automatically.

RelationExtractor

from semantica.semantic_extract import RelationExtractor

rel = RelationExtractor(method="llm", llm_provider=llm, max_retries=3)
relationships = rel.extract(text, entities=entities)

Output format:

[
    {"subject": "Steve Jobs", "predicate": "founded",    "object": "Apple Inc.", "confidence": 0.92},
    {"subject": "Apple Inc.", "predicate": "located_in", "object": "Cupertino",  "confidence": 0.89}
]

Available methods: "rule" (pattern-based), "ml" (REBEL model), "llm".

TripletExtractor

Generate RDF-ready (subject, predicate, object) triplets directly from text:

from semantica.semantic_extract import TripletExtractor

trip = TripletExtractor(method="llm", llm_provider=llm)
triplets = trip.extract(text)
# → [{"subject": "Steve Jobs", "predicate": "founded", "object": "Apple Inc.", ...}]

Triplets are suitable for loading directly into a triplet store or knowledge graph.

EventDetector

Detect events with participants and temporal context:

from semantica.semantic_extract import EventDetector, Event

extractor = EventDetector(method="llm", llm_provider=llm)
events: list[Event] = extractor.extract(text)

for event in events:
    print(f"Event type:   {event.type}")
    print(f"Participants: {event.participants}")
    print(f"Temporal:     {event.temporal}")
    print(f"Confidence:   {event.confidence:.2f}")

Output fields per event: type, participants (with roles), temporal, location, and confidence.

CoreferenceResolver

Resolve pronoun and alias references to canonical entities before extraction:

from semantica.semantic_extract import CoreferenceResolver

resolver = CoreferenceResolver()
resolved_text = resolver.resolve(
    "Apple Inc. was founded in 1976. The company is headquartered in Cupertino."
)
# "Apple Inc." replaces "The company" for consistent downstream extraction

Batch Processing

All extractors support batch input for efficient large-scale processing:

texts = ["Text 1...", "Text 2...", "Text 3..."]

ner = NERExtractor(method="llm", llm_provider=llm)
batch_results = ner.extract_batch(texts, batch_size=10)

Using All Extractors Together

The standard extraction pipeline — entities → relationships → triplets:

from semantica.semantic_extract import NERExtractor, RelationExtractor, TripletExtractor
from semantica.llms import Groq
import os

llm = Groq(model="llama-3.3-70b-versatile", api_key=os.getenv("GROQ_API_KEY"))

ner  = NERExtractor(method="llm",      llm_provider=llm, max_retries=3)
rel  = RelationExtractor(method="llm", llm_provider=llm, max_retries=3)
trip = TripletExtractor(method="llm",  llm_provider=llm, max_retries=3)

entities      = ner.extract(text)
relationships = rel.extract(text, entities=entities)
triplets      = trip.extract(text)

Extraction Method Comparison

Method	Speed	Cost	Accuracy	Custom Types
pattern	Very fast	Free	Medium	Yes (dictionary)
ml	Fast	Free	High	Limited
llm	Medium	API cost	Highest	Yes (schema)

Configure which LLM is used for extraction. Build graphs from extracted entities and relationships. Parse documents before extraction. Resolve duplicate entities after extraction.