core/tests/test_versor_closure.py
Shay 9723941a38
Fail closed on invalid versor construction
Make versor construction fail closed instead of synthesizing hash-derived fallback rotors.

- remove pseudo-random construction fallback from unitize_versor
- add signed residual helper for +1 field states vs ±1 manifold entries
- validate vocab manifold entries with full residuals
- document antipodal transition rotor failure contract
- add focused invariant tests for versor closure and manifold validation
2026-05-14 10:55:11 -07:00

111 lines
3.2 KiB
Python

"""
CRITICAL: This test must pass before any other file is extended.
It verifies the core algebraic invariant of the entire system.
"""
import numpy as np
import pytest
from hypothesis import given, settings
from hypothesis import strategies as st
from algebra.rotor import word_transition_rotor
from algebra.versor import (
unitize_versor,
versor_apply,
versor_condition,
versor_unit_residual,
)
def _positive_unit_reflector(seed=None) -> np.ndarray:
"""
Construct a true positive-norm Cl(4,1) grade-1 versor.
The current field action uses V * F * reverse(V), so the operator fixture
must satisfy V * reverse(V) = +1, not -1. We therefore keep the fifth
basis component bounded below the positive four-space norm.
"""
rng = np.random.default_rng(seed)
vec4 = rng.standard_normal(4).astype(np.float32)
norm4 = float(np.linalg.norm(vec4))
if norm4 < 1e-6:
vec4[0] = 1.0
norm4 = 1.0
vec = np.zeros(5, dtype=np.float32)
vec[:4] = vec4
vec[4] = 0.25 * norm4 * np.tanh(float(rng.standard_normal()))
mv = np.zeros(32, dtype=np.float32)
mv[1:6] = vec
return unitize_versor(mv)
@given(st.integers(min_value=0, max_value=99))
@settings(max_examples=100)
def test_versor_apply_preserves_manifold(seed):
V = _positive_unit_reflector(seed)
F = _positive_unit_reflector(seed + 1000)
result = versor_apply(V, F)
cond = versor_condition(result)
assert cond < 1e-4, f"versor_apply broke the manifold: condition={cond:.2e}"
def test_unitize_clean_scalar_constructs_positive_unit_versor():
raw = np.zeros(32, dtype=np.float32)
raw[0] = 2.0
V = unitize_versor(raw)
assert np.allclose(V[0], 1.0, atol=1e-7)
assert versor_condition(V) < 1e-7
def test_unitize_rejects_non_scalar_residue_instead_of_hash_fallback():
dirty = np.zeros(32, dtype=np.float32)
dirty[0] = np.sqrt(0.5)
dirty[1] = np.sqrt(0.5)
with pytest.raises(ValueError, match="bad_residue"):
unitize_versor(dirty)
def test_unitize_rejects_non_positive_scalar_norm():
negative_norm = np.zeros(32, dtype=np.float32)
negative_norm[5] = 1.0
with pytest.raises(ValueError, match="bad_scalar"):
unitize_versor(negative_norm)
def test_versor_unit_residual_can_accept_signed_manifold_versors():
negative_norm = np.zeros(32, dtype=np.float32)
negative_norm[5] = 1.0
assert versor_condition(negative_norm) > 1.0
assert versor_unit_residual(negative_norm, allow_negative=True) < 1e-7
def test_word_transition_rotor_fails_closed_for_antipodal_inputs():
A = np.zeros(32, dtype=np.float32)
A[0] = 1.0
B = np.zeros(32, dtype=np.float32)
B[0] = -1.0
with pytest.raises(ValueError, match="near_zero"):
word_transition_rotor(A, B)
def test_composition_closed():
V1 = _positive_unit_reflector(0)
V2 = _positive_unit_reflector(1)
F = _positive_unit_reflector(2)
F2 = versor_apply(V1, F)
F3 = versor_apply(V2, F2)
assert versor_condition(F3) < 1e-4
def test_identity_versor():
identity = np.zeros(32, dtype=np.float32)
identity[0] = 1.0
F = _positive_unit_reflector(42)
result = versor_apply(identity, F)
assert np.allclose(result, F, atol=1e-5)