Datasets:
Formats:
json
Languages:
English
Size:
< 1K
Tags:
mathematics
tensor-tomography
inverse-problems
positive-sensing
reproducible-research
Synthetic
Download research/code/test_coded_channels.py from PureOne/EVE-AEQIRION: direct link, hf CLI and curl.
- Browser
- Download file 12.8 kB
-
https://huggingface.co/datasets/PureOne/EVE-AEQIRION/resolve/main/research/code/test_coded_channels.py
- Command line
-
hf download hf://datasets/PureOne/EVE-AEQIRION/research/code/test_coded_channels.py
-
curl -L -o test_coded_channels.py https://huggingface.co/datasets/PureOne/EVE-AEQIRION/resolve/main/research/code/test_coded_channels.py
12.8 kB
| #!/usr/bin/env python3 | |
| """Exact tests of optimal positive-mask coordinate tomography. | |
| Python 3.10+, standard library only. All ranks, sensors, reconstruction and | |
| noise certificates use rational arithmetic. The mask-partition routine uses | |
| the shortest exchange augmentation for representable matroid partition and | |
| checks every returned partition explicitly. No novel matroid algorithm is | |
| claimed. The manuscript attributes the partition criterion to Edmonds. | |
| """ | |
| from collections import deque | |
| from fractions import Fraction as F | |
| from itertools import product | |
| from math import prod | |
| import json | |
| import random | |
| def rank(vectors): | |
| """Rank of vectors, each represented as a sequence of rational numbers.""" | |
| basis = {} | |
| for vector in vectors: | |
| row = list(map(F, vector)) | |
| for pivot, prior in sorted(basis.items()): | |
| if row[pivot]: | |
| scalar = row[pivot] | |
| row = [a - scalar * b for a, b in zip(row, prior)] | |
| pivot = next((i for i, value in enumerate(row) if value), None) | |
| if pivot is not None: | |
| scalar = row[pivot] | |
| basis[pivot] = [value / scalar for value in row] | |
| return len(basis) | |
| def independent_rows(rows): | |
| chosen = [] | |
| previous = 0 | |
| for i, row in enumerate(rows): | |
| current = rank([rows[j] for j in chosen] + [row]) | |
| if current > previous: | |
| chosen.append(i) | |
| previous = current | |
| return chosen | |
| def solve_linear(rows, rhs): | |
| """A consistent linear system, with all nonpivot variables set to zero.""" | |
| assert rows and len(rows) == len(rhs) | |
| n = len(rows[0]) | |
| matrix = [list(map(F, row)) + [F(value)] for row, value in zip(rows, rhs)] | |
| pivots = [] | |
| lead = 0 | |
| for col in range(n): | |
| selected = next((i for i in range(lead, len(matrix)) if matrix[i][col]), None) | |
| if selected is None: | |
| continue | |
| matrix[lead], matrix[selected] = matrix[selected], matrix[lead] | |
| scalar = matrix[lead][col] | |
| matrix[lead] = [value / scalar for value in matrix[lead]] | |
| for i in range(len(matrix)): | |
| if i != lead and matrix[i][col]: | |
| scalar = matrix[i][col] | |
| matrix[i] = [a - scalar * b for a, b in zip(matrix[i], matrix[lead])] | |
| pivots.append(col) | |
| lead += 1 | |
| if lead == len(matrix): | |
| break | |
| for row in matrix: | |
| assert any(row[:n]) or row[n] == 0, 'inconsistent linear system' | |
| answer = [F(0)] * n | |
| for i, col in enumerate(pivots): | |
| answer[col] = matrix[i][-1] | |
| assert [sum(a * b for a, b in zip(row, answer)) for row in rows] == list(rhs) | |
| return answer | |
| def inverse(matrix): | |
| n = len(matrix) | |
| assert all(len(row) == n for row in matrix) | |
| columns = [solve_linear(matrix, [F(i == j) for i in range(n)]) for j in range(n)] | |
| return [[columns[j][i] for j in range(n)] for i in range(n)] | |
| def matvec(matrix, vector): | |
| return [sum((F(a) * b for a, b in zip(row, vector)), F(0)) for row in matrix] | |
| def coordinate_operator(shape): | |
| """Every row sums a coordinate fiber; columns are labeled grid cells.""" | |
| points = list(product(*(range(q) for q in shape))) | |
| rows, labels = [], [] | |
| for axis in range(len(shape)): | |
| other_shape = [q for i, q in enumerate(shape) if i != axis] | |
| for kept in product(*(range(q) for q in other_shape)): | |
| rows.append([int(tuple(x for i, x in enumerate(point) if i != axis) == kept) | |
| for point in points]) | |
| labels.append((axis, kept)) | |
| return points, rows, labels | |
| def independent_partition(matrix, channels): | |
| """Shortest exchange augmentation; independent sets cover the columns.""" | |
| count = len(matrix[0]) | |
| columns = [tuple(row[j] for row in matrix) for j in range(count)] | |
| groups = [set() for _ in range(channels)] | |
| tests = 0 | |
| def independent(indices): | |
| nonlocal tests | |
| tests += 1 | |
| return rank([columns[j] for j in sorted(indices)]) == len(indices) | |
| for element in range(count): | |
| queue = deque([element]) | |
| previous = {element: None} | |
| terminal = None | |
| while queue and terminal is None: | |
| current = queue.popleft() | |
| for color, group in enumerate(groups): | |
| if current in group: | |
| continue | |
| if independent(group | {current}): | |
| terminal = (current, color) | |
| break | |
| for displaced in sorted(group): | |
| if displaced not in previous and independent((group - {displaced}) | {current}): | |
| previous[displaced] = (current, color) | |
| queue.append(displaced) | |
| assert terminal is not None, 'requested channel count does not admit a partition' | |
| revised = [group.copy() for group in groups] | |
| current, color = terminal | |
| revised[color].add(current) | |
| while previous[current] is not None: | |
| predecessor, color = previous[current] | |
| revised[color].remove(current) | |
| revised[color].add(predecessor) | |
| current = predecessor | |
| assert set().union(*revised) == set(range(element + 1)) | |
| assert sum(map(len, revised)) == element + 1 | |
| assert all(independent(group) for group in revised) | |
| groups = revised | |
| # Enlarge the first independent set to a basis by moving elements from | |
| # the others. Removing an element cannot spoil their independence. | |
| full_rank = rank(columns) | |
| while len(groups[0]) < full_rank: | |
| move = next((element for group in groups[1:] for element in sorted(group) | |
| if independent(groups[0] | {element})), None) | |
| assert move is not None | |
| source = next(j for j in range(1, channels) if move in groups[j]) | |
| groups[source].remove(move) | |
| groups[0].add(move) | |
| assert all(independent(group) for group in groups) | |
| return [sorted(group) for group in groups], tests | |
| def sensor_plan(matrix, groups, low=F(1, 4), high=F(1)): | |
| """Exactly N scalar rows, using one baseline and positive two-level masks.""" | |
| assert 0 < low < high | |
| n = len(matrix[0]) | |
| baseline_rows = independent_rows(matrix) | |
| selected = [baseline_rows] | |
| masks = [[F(1)] * n] | |
| operator = [[F(x) for x in matrix[i]] for i in baseline_rows] | |
| for group in groups[1:]: | |
| restricted = [[row[j] for j in group] for row in matrix] | |
| choices = independent_rows(restricted) | |
| assert len(choices) == len(group) | |
| selected.append(choices) | |
| mask = [high if j in group else low for j in range(n)] | |
| masks.append(mask) | |
| operator.extend([[F(a) * w for a, w in zip(matrix[i], mask)] for i in choices]) | |
| assert len(operator) == n | |
| assert rank(operator) == n | |
| return {'selected': selected, 'masks': masks, 'operator': operator, | |
| 'low': low, 'high': high} | |
| def decode(matrix, groups, plan, observations): | |
| """Reconstruct from only the N selected scalar measurements.""" | |
| n = len(matrix[0]) | |
| rb = plan['selected'][0] | |
| r = len(rb) | |
| base_particular = solve_linear([matrix[i] for i in rb], observations[:r]) | |
| full_baseline = matvec(matrix, base_particular) | |
| answer = [F(0)] * n | |
| pointer = r | |
| for group, choices in zip(groups[1:], plan['selected'][1:]): | |
| values = observations[pointer:pointer + len(choices)] | |
| pointer += len(choices) | |
| isolated = [(value - plan['low'] * full_baseline[i]) / | |
| (plan['high'] - plan['low']) for value, i in zip(values, choices)] | |
| local = solve_linear([[matrix[i][j] for j in group] for i in choices], isolated) | |
| for j, value in zip(group, local): | |
| answer[j] = value | |
| assert pointer == n | |
| residual = [full_baseline[i] - sum(F(matrix[i][j]) * answer[j] | |
| for group in groups[1:] for j in group) for i in rb] | |
| first = solve_linear([[matrix[i][j] for j in groups[0]] for i in rb], residual) | |
| for j, value in zip(groups[0], first): | |
| answer[j] = value | |
| return answer | |
| def norm_inf(matrix): | |
| return max(sum(abs(x) for x in row) for row in matrix) | |
| def case(shape): | |
| points, matrix, row_labels = coordinate_operator(shape) | |
| n = prod(shape) | |
| blind = prod(q - 1 for q in shape) | |
| r = n - blind | |
| assert rank(matrix) == r | |
| channels = (n + r - 1) // r | |
| groups, oracle_tests = independent_partition(matrix, channels) | |
| assert len(groups[0]) == r | |
| assert sum(map(len, groups)) == n | |
| plan = sensor_plan(matrix, groups) | |
| rng = random.Random(1000 + n) | |
| recovered = 0 | |
| for _ in range(8): | |
| z = [F(rng.randint(1, 80), rng.randint(1, 17)) for _ in points] | |
| observations = matvec(plan['operator'], z) | |
| assert decode(matrix, groups, plan, observations) == z | |
| recovered += 1 | |
| # A certified linear-noise bound, with a worst-case perturbation attaining | |
| # it: pick the sign of the largest absolute-row-sum inverse row. | |
| inv = inverse(plan['operator']) | |
| gain = norm_inf(inv) | |
| z = [F(i + 2, 7) for i in range(n)] | |
| epsilon = min(z) / (10 * gain) | |
| worst_row = max(range(n), key=lambda j: sum(abs(x) for x in inv[j])) | |
| error = [epsilon * (1 if x > 0 else -1 if x < 0 else 0) for x in inv[worst_row]] | |
| observations = matvec(plan['operator'], z) | |
| noisy = [a + b for a, b in zip(observations, error)] | |
| estimate = decode(matrix, groups, plan, noisy) | |
| actual_error = max(abs(a - b) for a, b in zip(estimate, z)) | |
| assert actual_error == gain * epsilon | |
| assert min(estimate) > 0 | |
| # Fewer channels cannot be injective, independently of how masks are | |
| # chosen. Sample several positive masks to check the rank obstruction. | |
| lower_rank_tests = [] | |
| if channels > 1: | |
| assert (channels - 1) * r < n | |
| for seed in range(3): | |
| rg = random.Random(seed) | |
| stacked = [] | |
| for j in range(channels - 1): | |
| weights = [F(1) if j == 0 else F(rg.randint(1, 9)) for _ in points] | |
| stacked.extend([[F(a) * w for a, w in zip(row, weights)] for row in matrix]) | |
| observed_rank = rank(stacked) | |
| assert observed_rank <= (channels - 1) * r < n | |
| lower_rank_tests.append(observed_rank) | |
| all_temperature_checks = 0 | |
| if len(set(shape)) == 1 and len(shape) >= 2: | |
| q = shape[0] | |
| z0 = [F(2 if sum(point) % q == 0 else 5) for point in points] | |
| z1 = [F(2 if sum(point) % q == 1 else 5) for point in points] | |
| assert z0 != z1 | |
| for row in matrix: | |
| values0 = sorted(z0[j] for j, a in enumerate(row) if a) | |
| values1 = sorted(z1[j] for j, a in enumerate(row) if a) | |
| assert values0 == values1 | |
| for power in range(1, q + 3): | |
| assert sum(x ** power for x in values0) == sum(x ** power for x in values1) | |
| all_temperature_checks += 1 | |
| for z in (z0, z1): | |
| assert decode(matrix, groups, plan, matvec(plan['operator'], z)) == z | |
| return {'shape': list(shape), 'cells': n, 'unmasked_rank': r, | |
| 'blind_dimension': blind, 'optimal_channels': channels, | |
| 'partition_sizes': list(map(len, groups)), | |
| 'partition': groups, 'partition_independence_oracle_calls': oracle_tests, | |
| 'scalar_measurements': len(plan['operator']), | |
| 'selected_fiber_rows': plan['selected'], | |
| 'positive_mask_levels': [str(plan['low']), str(plan['high'])], | |
| 'selected_operator_rank': rank(plan['operator']), | |
| 'exact_rational_recoveries': recovered, | |
| 'inverse_inf_norm': str(gain), | |
| 'condition_number_inf': str(norm_inf(plan['operator']) * gain), | |
| 'sharp_noise_certificate': True, | |
| 'fewer_channel_sample_ranks': lower_rank_tests, | |
| 'unmodulated_multiset_power_equalities': all_temperature_checks, | |
| 'coded_recovery_of_both_ambiguous_fields': True if all_temperature_checks else None} | |
| def main(): | |
| cases = [case(shape) for shape in ((3, 3), (4, 4), (3, 3, 3), (2, 3, 4))] | |
| cases.extend(case((2,) * dim) for dim in range(1, 6)) | |
| return {'status': 'PASS', 'arithmetic': 'exact integers and fractions', | |
| 'cases': cases, | |
| 'scope': ['Mask channels interrogate the same fixed positive field.', | |
| 'Masks are calibrated, externally supplied additional observations.', | |
| 'Optimality is within the stated linear exponential-domain sensor model.', | |
| 'The matroid partition criterion is established mathematics.', | |
| 'No practical image or neural-network superiority is tested.']} | |
| if __name__ == '__main__': | |
| print(json.dumps(main(), indent=2)) | |