File size: 5,024 Bytes
5f07cd7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | import numpy as np
from typing import Dict
DIM = 10_000
SEED = 42
_rng = np.random.default_rng(SEED)
# Bipolar base vectors (-1/1) to match hdc_engine.bind and VitalisKernel
BASE_MFCC = _rng.choice([-1, 1], size=(13, DIM)).astype(np.int8)
BASE_PROSODY = {
"pitch": _rng.choice([-1, 1], size=DIM).astype(np.int8),
"energy": _rng.choice([-1, 1], size=DIM).astype(np.int8),
"tempo": _rng.choice([-1, 1], size=DIM).astype(np.int8),
"pause_ratio": _rng.choice([-1, 1], size=DIM).astype(np.int8),
}
PROSODY_SCALE = {
"pitch": 300.0,
"energy": 0.5,
"tempo": 200.0,
"pause_ratio": 1.0,
}
def _bipolar_binarize(val: float) -> np.ndarray:
"""Map a scalar [0,1] to a bipolar hypervector."""
bits = (_rng.random(DIM) < val).astype(np.int8)
bits[bits == 0] = -1
return bits
def _permute(vec: np.ndarray, shift: int) -> np.ndarray:
"""Cyclic shift — encodes temporal position."""
return np.roll(vec, shift % DIM)
def _bind(a: np.ndarray, b: np.ndarray) -> np.ndarray:
"""Bipolar binding: element-wise multiply (-1/1 * -1/1 = -1/1)."""
return (a * b).astype(np.int8)
def _bundle(vecs: list) -> np.ndarray:
"""
Bipolar bundling: sum then binarize via sign.
Ties broken toward +1.
"""
stacked = np.stack(vecs, axis=0).astype(np.int32)
result = np.sign(stacked.sum(axis=0)).astype(np.int8)
result[result == 0] = 1
return result
def encode(
mfcc: np.ndarray,
prosody: Dict[str, float],
chunk_size: int = 5,
) -> np.ndarray:
"""
Convert one utterance (MFCC matrix + prosody dict) into a single
bipolar 10k-dim hypervector that preserves temporal order.
Temporal encoding equation:
S = V_1 * rho(V_2) * rho^2(V_3) ... rho^n(V_n)
where rho is cyclic shift and * is bipolar binding.
"""
n_frames = mfcc.shape[1]
# ------------------------------------------------------------------
# 1. Frame-level bipolar vectors
# Each frame: 13 MFCC coefficients bound with their base vectors
# ------------------------------------------------------------------
frame_hvs = []
for t in range(n_frames):
frame_components = []
for i in range(13):
coeff_val = float(mfcc[i, t])
# Threshold against coefficient median → bipolar
bit = np.int8(1) if coeff_val > 0 else np.int8(-1)
coeff_vec = np.full(DIM, bit, dtype=np.int8)
frame_components.append(_bind(coeff_vec, BASE_MFCC[i]))
frame_hvs.append(_bundle(frame_components))
# ------------------------------------------------------------------
# 2. Forward temporal binding (preserves order)
# S_fwd = frame_0 * rho(frame_1) * rho^2(frame_2) ...
# ------------------------------------------------------------------
forward_hv = frame_hvs[0].copy() if frame_hvs else np.ones(DIM, dtype=np.int8)
for t in range(1, len(frame_hvs)):
forward_hv = _bind(forward_hv, _permute(frame_hvs[t], shift=t))
# ------------------------------------------------------------------
# 3. Backward temporal binding (reverse rhythm)
# ------------------------------------------------------------------
backward_hv = frame_hvs[-1].copy() if frame_hvs else np.ones(DIM, dtype=np.int8)
for t in range(len(frame_hvs) - 2, -1, -1):
backward_hv = _bind(backward_hv, _permute(frame_hvs[t], shift=-(t + 1)))
# ------------------------------------------------------------------
# 4. Chunk-level binding (mid-scale temporal structure)
# ------------------------------------------------------------------
n_chunks = max(1, n_frames // chunk_size)
chunk_hvs = []
for c in range(n_chunks):
start = c * chunk_size
end = min(start + chunk_size, n_frames)
chunk_bundle = _bundle(frame_hvs[start:end])
chunk_hvs.append(_permute(chunk_bundle, shift=c))
chunk_hv = _bundle(chunk_hvs) if chunk_hvs else np.ones(DIM, dtype=np.int8)
# ------------------------------------------------------------------
# 5. Prosody binding (tone, energy, rhythm, silence)
# Each prosody feature bound with its base vector and
# permuted by frame count (ties prosody to utterance length)
# ------------------------------------------------------------------
prosody_hvs = []
for key, val in prosody.items():
norm = min(val / PROSODY_SCALE.get(key, 1.0), 1.0)
pv = _bind(_bipolar_binarize(norm), BASE_PROSODY[key])
pv = _permute(pv, shift=n_frames)
prosody_hvs.append(pv)
# ------------------------------------------------------------------
# 6. Final composition: bundle all levels
# forward captures sequence, backward captures rhythm,
# chunks capture phrase structure, prosody captures tone
# ------------------------------------------------------------------
all_components = [forward_hv, backward_hv, chunk_hv] + prosody_hvs
return _bundle(all_components)
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