ato 2.1.0

Configuration, experimentation, and hyperparameter optimization for Python. No runtime magic. No launcher. Just Python modules you compose.

Ato: A Tiny Orchestrator

Configuration, experimentation, and hyperparameter optimization for Python.

No runtime magic. No launcher. No platform. Just Python modules you compose.

pip install ato

---

Design Philosophy

Ato was built on three constraints:

1. Visibility — When configs merge from multiple sources, you should see why a value was set.
2. Composability — Each module (ADict, Scope, SQLTracker, HyperOpt) works independently. Use one, use all, or mix with other tools.
3. Structural neutrality — Ato is a layer, not a platform. It has no opinion on your stack.

This isn't minimalism for its own sake. It's structural restraint — interfering only where necessary, staying out of the way everywhere else.

What Ato provides:

• Config composition with explicit priority and merge order debugging
• Namespace isolation for multi-team projects (MultiScope)
• Experiment tracking in local SQLite with zero setup
• Hyperparameter search via Hyperband (or compose with Optuna/Ray Tune)

What Ato doesn't provide:

• Web dashboards (use MLflow/W&B)
• Model registry (use MLflow)
• Dataset versioning (use DVC)
• Plugin marketplace

Ato is designed to work between tools, not replace them.

---

Quick Start

30-Second Example

from ato.scope import Scope

scope = Scope()

@scope.observe(default=True)
def config(config):
    config.lr = 0.001
    config.batch_size = 32
    config.model = 'resnet50'

@scope
def train(config):
    print(f"Training {config.model} with lr={config.lr}")
    # Your training code here

if __name__ == '__main__':
    train()  # python train.py
    # Override from CLI: python train.py lr=0.01 model=%resnet101%

Key features:

• @scope.observe() defines config sources
• @scope injects the merged config
• CLI overrides work automatically
• Priority-based merging (defaults → named configs → CLI → lazy evaluation)

---

Table of Contents

• ADict: Enhanced Dictionary
• Scope: Configuration Management
  • MultiScope: Namespace Isolation
  • Config Documentation & Debugging
• SQL Tracker: Experiment Tracking
• Hyperparameter Optimization
• Best Practices
• Contributing
• Composability

---

ADict: Enhanced Dictionary

ADict is an enhanced dictionary for managing experiment configurations.

Core Features

Feature	Description	Why It Matters
Structural Hashing	Hash based on keys + types, not values	Track when experiment structure changes (not just hyperparameters)
Nested Access	Dot notation for nested configs	config.model.lr instead of config['model']['lr']
Format Agnostic	Load/save JSON, YAML, TOML, XYZ	Work with any config format
Safe Updates	update_if_absent() method	Merge configs without accidental overwrites
Auto-nested	ADict.auto() for lazy creation	config.a.b.c = 1 just works - no KeyError

Examples

Structural Hashing

from ato.adict import ADict

# Same structure, different values
config1 = ADict(lr=0.1, epochs=100, model='resnet50')
config2 = ADict(lr=0.01, epochs=200, model='resnet101')
print(config1.get_structural_hash() == config2.get_structural_hash())  # True

# Different structure (epochs is str!)
config3 = ADict(lr=0.1, epochs='100', model='resnet50')
print(config1.get_structural_hash() == config3.get_structural_hash())  # False

Auto-nested Configs

# ❌ Traditional way
config = ADict()
config.model = ADict()
config.model.backbone = ADict()
config.model.backbone.layers = [64, 128, 256]

# ✅ With ADict.auto()
config = ADict.auto()
config.model.backbone.layers = [64, 128, 256]  # Just works!
config.data.augmentation.brightness = 0.2

Format Agnostic

# Load/save any format
config = ADict.from_file('config.json')
config.dump('config.yaml')

# Safe updates
config.update_if_absent(lr=0.01, scheduler='cosine')  # Only adds scheduler

---

Scope: Configuration Management

Scope manages configuration through priority-based merging and CLI integration.

Key Concept: Priority Chain

Default Configs (priority=0)
    ↓
Named Configs (priority=0+)
    ↓
CLI Arguments (highest priority)
    ↓
Lazy Configs (computed after CLI)

Basic Usage

Simple Configuration

from ato.scope import Scope

scope = Scope()

@scope.observe()
def my_config(config):
    config.dataset = 'cifar10'
    config.lr = 0.001
    config.batch_size = 32

@scope
def train(config):
    print(f"Training on {config.dataset}")
    # Your code here

if __name__ == '__main__':
    train()

Priority-based Merging

@scope.observe(default=True)  # Always applied
def defaults(config):
    config.lr = 0.001
    config.epochs = 100

@scope.observe(priority=1)  # Applied after defaults
def high_lr(config):
    config.lr = 0.01

@scope.observe(priority=2)  # Applied last
def long_training(config):
    config.epochs = 300

python train.py                           # lr=0.001, epochs=100
python train.py high_lr                   # lr=0.01, epochs=100
python train.py high_lr long_training     # lr=0.01, epochs=300

CLI Configuration

Override any parameter from command line:

# Simple values
python train.py lr=0.01 batch_size=64

# Nested configs
python train.py model.backbone=%resnet101% model.depth=101

# Lists and complex types
python train.py layers=[64,128,256,512] dropout=0.5

# Combine with named configs
python train.py my_config lr=0.001 batch_size=128

Note: Wrap strings with % (e.g., %resnet101%) instead of quotes.

Lazy Evaluation

Sometimes you need configs that depend on other values set via CLI:

@scope.observe()
def base_config(config):
    config.model = 'resnet50'
    config.dataset = 'imagenet'

@scope.observe(lazy=True)  # Evaluated AFTER CLI args
def computed_config(config):
    # Adjust based on dataset
    if config.dataset == 'imagenet':
        config.num_classes = 1000
        config.image_size = 224
    elif config.dataset == 'cifar10':
        config.num_classes = 10
        config.image_size = 32

python train.py dataset=%cifar10% computed_config
# Results in: num_classes=10, image_size=32

Python 3.11+ Context Manager:

@scope.observe()
def my_config(config):
    config.model = 'resnet50'
    config.num_layers = 50

    with Scope.lazy():  # Evaluated after CLI
        if config.model == 'resnet101':
            config.num_layers = 101

MultiScope: Namespace Isolation

Manage completely separate configuration namespaces with independent priority systems.

Use case: Different teams own different scopes without key collisions.

from ato.scope import Scope, MultiScope

model_scope = Scope(name='model')
data_scope = Scope(name='data')
scope = MultiScope(model_scope, data_scope)

@model_scope.observe(default=True)
def model_config(model):
    model.backbone = 'resnet50'
    model.lr = 0.1  # Model-specific learning rate

@data_scope.observe(default=True)
def data_config(data):
    data.dataset = 'cifar10'
    data.lr = 0.001  # Data augmentation learning rate (no conflict!)

@scope
def train(model, data):  # Named parameters match scope names
    # Both have 'lr' but in separate namespaces!
    print(f"Model LR: {model.lr}, Data LR: {data.lr}")

Key advantage: model.lr and data.lr are completely independent. No need for naming conventions like model_lr vs data_lr.

CLI with MultiScope:

# Override model scope only
python train.py model.backbone=%resnet101%

# Override data scope only
python train.py data.dataset=%imagenet%

# Override both
python train.py model.backbone=%resnet101% data.dataset=%imagenet%

Configuration Documentation & Debugging

The manual command visualizes the exact order of configuration application.

@scope.observe(default=True)
def config(config):
    config.lr = 0.001
    config.batch_size = 32
    config.model = 'resnet50'

@scope.manual
def config_docs(config):
    config.lr = 'Learning rate for optimizer'
    config.batch_size = 'Number of samples per batch'
    config.model = 'Model architecture (resnet50, resnet101, etc.)'

python train.py manual

Output:

--------------------------------------------------
[Scope "config"]
(The Applying Order of Views)
config → (CLI Inputs)

(User Manuals)
lr: Learning rate for optimizer
batch_size: Number of samples per batch
model: Model architecture (resnet50, resnet101, etc.)
--------------------------------------------------

Why this matters: When debugging "why is this config value not what I expect?", you can see exactly which function set it and in what order.

Complex example:

@scope.observe(default=True)
def defaults(config):
    config.lr = 0.001

@scope.observe(priority=1)
def experiment_config(config):
    config.lr = 0.01

@scope.observe(priority=2)
def another_config(config):
    config.lr = 0.1

@scope.observe(lazy=True)
def adaptive_lr(config):
    if config.batch_size > 64:
        config.lr = config.lr * 2

When you run python train.py manual, you see:

(The Applying Order of Views)
defaults → experiment_config → another_config → (CLI Inputs) → adaptive_lr

Now it's crystal clear why lr=0.1 (from another_config) and not 0.01!

Config Import/Export

@scope.observe()
def load_external(config):
    # Load from any format
    config.load('experiments/baseline.json')
    config.load('models/resnet.yaml')

    # Export to any format
    config.dump('output/final_config.toml')

OpenMMLab compatibility:

# Import OpenMMLab configs - handles _base_ inheritance automatically
config.load_mm_config('mmdet_configs/faster_rcnn.py')

Hierarchical composition:

from ato.adict import ADict

# Load configs from directory structure
config = ADict.compose_hierarchy(
    root='configs',
    config_filename='config',
    select={
        'model': 'resnet50',
        'data': 'imagenet'
    },
    overrides={
        'model.lr': 0.01,
        'data.batch_size': 64
    },
    required=['model.backbone', 'data.dataset'],  # Validation
    on_missing='warn'  # or 'error'
)

Argparse Integration

from ato.scope import Scope
import argparse

scope = Scope(use_external_parser=True)
parser = argparse.ArgumentParser()
parser.add_argument('--gpu', type=int, default=0)
parser.add_argument('--seed', type=int, default=42)

@scope.observe(default=True)
def config(config):
    config.lr = 0.001
    config.batch_size = 32

@scope
def train(config):
    print(f"GPU: {config.gpu}, LR: {config.lr}")

if __name__ == '__main__':
    parser.parse_args()  # Merges argparse with scope
    train()

---

SQL Tracker: Experiment Tracking

Lightweight experiment tracking using SQLite.

Why SQL Tracker?

• Zero Setup: Just a SQLite file, no servers
• Full History: Track all runs, metrics, and artifacts
• Smart Search: Find similar experiments by config structure
• Code Versioning: Track code changes via fingerprints
• Offline-first: No network required, sync to cloud tracking later if needed

Database Schema

Project (my_ml_project)
├── Experiment (run_1)
│   ├── config: {...}
│   ├── structural_hash: "abc123..."
│   ├── Metrics: [loss, accuracy, ...]
│   ├── Artifacts: [model.pt, plots/*, ...]
│   └── Fingerprints: [model_forward, train_step, ...]
├── Experiment (run_2)
└── ...

Usage

Logging Experiments

from ato.db_routers.sql.manager import SQLLogger
from ato.adict import ADict

# Setup config
config = ADict(
    experiment=ADict(
        project_name='image_classification',
        sql=ADict(db_path='sqlite:///experiments.db')
    ),
    # Your hyperparameters
    lr=0.001,
    batch_size=32,
    model='resnet50'
)

# Create logger
logger = SQLLogger(config)

# Start experiment run
run_id = logger.run(tags=['baseline', 'resnet50', 'cifar10'])

# Training loop
for epoch in range(100):
    # Your training code
    train_loss = train_one_epoch()
    val_acc = validate()

    # Log metrics
    logger.log_metric('train_loss', train_loss, step=epoch)
    logger.log_metric('val_accuracy', val_acc, step=epoch)

# Log artifacts
logger.log_artifact(run_id, 'checkpoints/model_best.pt',
                   data_type='model',
                   metadata={'epoch': best_epoch})

# Finish run
logger.finish(status='completed')

Querying Experiments

from ato.db_routers.sql.manager import SQLFinder

finder = SQLFinder(config)

# Get all runs in project
runs = finder.get_runs_in_project('image_classification')
for run in runs:
    print(f"Run {run.id}: {run.config.model} - {run.status}")

# Find best performing run
best_run = finder.find_best_run(
    project_name='image_classification',
    metric_key='val_accuracy',
    mode='max'  # or 'min' for loss
)
print(f"Best config: {best_run.config}")

# Find similar experiments (same config structure)
similar = finder.find_similar_runs(run_id=123)
print(f"Found {len(similar)} runs with similar config structure")

# Trace statistics (code fingerprints)
stats = finder.get_trace_statistics('image_classification', trace_id='model_forward')
print(f"Model forward pass has {stats['static_trace_versions']} versions")

Features

Feature	Description
Structural Hash	Auto-track config structure changes
Metric Logging	Time-series metrics with step tracking
Artifact Management	Track model checkpoints, plots, data files
Fingerprint Tracking	Version control for code (static & runtime)
Smart Search	Find similar configs, best runs, statistics

---

Hyperparameter Optimization

Built-in Hyperband algorithm for efficient hyperparameter search with early stopping.

How Hyperband Works

Hyperband uses successive halving:

1. Start with many configs, train briefly
2. Keep top performers, discard poor ones
3. Train survivors longer
4. Repeat until one winner remains

Basic Usage

from ato.adict import ADict
from ato.hyperopt.hyperband import HyperBand
from ato.scope import Scope

scope = Scope()

# Define search space
search_spaces = ADict(
    lr=ADict(
        param_type='FLOAT',
        param_range=(1e-5, 1e-1),
        num_samples=20,
        space_type='LOG'  # Logarithmic spacing
    ),
    batch_size=ADict(
        param_type='INTEGER',
        param_range=(16, 128),
        num_samples=5,
        space_type='LOG'
    ),
    model=ADict(
        param_type='CATEGORY',
        categories=['resnet50', 'resnet101', 'efficientnet_b0']
    )
)

# Create Hyperband optimizer
hyperband = HyperBand(
    scope,
    search_spaces,
    halving_rate=0.3,      # Keep top 30% each round
    num_min_samples=3,     # Stop when <= 3 configs remain
    mode='max'             # Maximize metric (use 'min' for loss)
)

@hyperband.main
def train(config):
    # Your training code
    model = create_model(config.model)
    optimizer = Adam(lr=config.lr)

    # Use __num_halved__ for early stopping
    num_epochs = compute_epochs(config.__num_halved__)

    # Train and return metric
    val_acc = train_and_evaluate(model, optimizer, num_epochs)
    return val_acc

if __name__ == '__main__':
    # Run hyperparameter search
    best_result = train()
    print(f"Best config: {best_result.config}")
    print(f"Best metric: {best_result.metric}")

Automatic Step Calculation

hyperband = HyperBand(scope, search_spaces, halving_rate=0.3, num_min_samples=4)

max_steps = 100000
steps_per_generation = hyperband.compute_optimized_initial_training_steps(max_steps)
# Example output: [27, 88, 292, 972, 3240, 10800, 36000, 120000]

# Use in training
@hyperband.main
def train(config):
    generation = config.__num_halved__
    num_steps = steps_per_generation[generation]

    metric = train_for_n_steps(num_steps)
    return metric

Parameter Types

Type	Description	Example
FLOAT	Continuous values	Learning rate, dropout
INTEGER	Discrete integers	Batch size, num layers
CATEGORY	Categorical choices	Model type, optimizer

Space types:

• LOG: Logarithmic spacing (good for learning rates)
• LINEAR: Linear spacing (default)

Distributed Search

from ato.hyperopt.hyperband import DistributedHyperBand
import torch.distributed as dist

# Initialize distributed training
dist.init_process_group(backend='nccl')
rank = dist.get_rank()
world_size = dist.get_world_size()

# Create distributed hyperband
hyperband = DistributedHyperBand(
    scope,
    search_spaces,
    halving_rate=0.3,
    num_min_samples=3,
    mode='max',
    rank=rank,
    world_size=world_size,
    backend='pytorch'
)

@hyperband.main
def train(config):
    # Your distributed training code
    model = create_model(config)
    model = DDP(model, device_ids=[rank])
    metric = train_and_evaluate(model)
    return metric

if __name__ == '__main__':
    result = train()
    if rank == 0:
        print(f"Best config: {result.config}")

Extensible Design

Ato's hyperopt module is built for extensibility:

Component	Purpose
GridSpaceMixIn	Parameter sampling logic (reusable)
HyperOpt	Base optimization class
DistributedMixIn	Distributed training support (optional)

Example: Implement custom search algorithm

from ato.hyperopt.base import GridSpaceMixIn, HyperOpt

class RandomSearch(GridSpaceMixIn, HyperOpt):
    def main(self, func):
        # Reuse GridSpaceMixIn.prepare_distributions()
        configs = self.prepare_distributions(self.config, self.search_spaces)

        # Implement random sampling
        import random
        random.shuffle(configs)

        results = []
        for config in configs[:10]:  # Sample 10 random configs
            metric = func(config)
            results.append((config, metric))

        return max(results, key=lambda x: x[1])

---

Best Practices

1. Project Structure

my_project/
├── configs/
│   ├── default.py       # Default config with @scope.observe(default=True)
│   ├── models.py        # Model-specific configs
│   └── datasets.py      # Dataset configs
├── train.py             # Main training script
├── experiments.db       # SQLite experiment tracking
└── experiments/
    ├── run_001/
    │   ├── checkpoints/
    │   └── logs/
    └── run_002/

2. Config Organization

# configs/default.py
from ato.scope import Scope
from ato.adict import ADict

scope = Scope()

@scope.observe(default=True)
def defaults(config):
    # Data
    config.data = ADict(
        dataset='cifar10',
        batch_size=32,
        num_workers=4
    )

    # Model
    config.model = ADict(
        backbone='resnet50',
        pretrained=True
    )

    # Training
    config.train = ADict(
        lr=0.001,
        epochs=100,
        optimizer='adam'
    )

    # Experiment tracking
    config.experiment = ADict(
        project_name='my_project',
        sql=ADict(db_path='sqlite:///experiments.db')
    )

3. Combined Workflow

from ato.scope import Scope
from ato.db_routers.sql.manager import SQLLogger
from configs.default import scope

@scope
def train(config):
    # Setup experiment tracking
    logger = SQLLogger(config)
    run_id = logger.run(tags=[config.model.backbone, config.data.dataset])

    try:
        # Training loop
        for epoch in range(config.train.epochs):
            loss = train_epoch()
            acc = validate()

            logger.log_metric('loss', loss, epoch)
            logger.log_metric('accuracy', acc, epoch)

        logger.finish(status='completed')

    except Exception as e:
        logger.finish(status='failed')
        raise e

if __name__ == '__main__':
    train()

4. Reproducibility Checklist

• ✅ Use structural hashing to track config changes
• ✅ Log all hyperparameters to SQLLogger
• ✅ Tag experiments with meaningful labels
• ✅ Track artifacts (checkpoints, plots)
• ✅ Use lazy configs for derived parameters
• ✅ Document configs with @scope.manual

---

Requirements

• Python >= 3.7
• SQLAlchemy (for SQL Tracker)
• PyYAML, toml (for config serialization)

See pyproject.toml for full dependencies.

---

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

Development Setup

git clone https://github.com/yourusername/ato.git
cd ato
pip install -e .

Quality Assurance

Ato's design philosophy — structural neutrality and debuggable composition — extends to our testing practices.

Release Policy:

• All 100+ unit tests must pass before any release
• No exceptions, no workarounds
• Tests cover every module: ADict, Scope, MultiScope, SQLTracker, HyperBand

Why this matters: When you build on Ato, you're trusting it to stay out of your way. That means zero regressions, predictable behavior, and reliable APIs. Comprehensive test coverage ensures that each component works independently and composes correctly.

Run tests locally:

python -m pytest unit_tests/

---

Composability

Ato is designed to compose with existing tools, not replace them.

Works Where Other Systems Require Ecosystems

Config composition:

• Import OpenMMLab configs: config.load_mm_config('mmdet_configs/faster_rcnn.py')
• Load Hydra-style hierarchies: ADict.compose_hierarchy(root='configs', select={'model': 'resnet50'})
• Mix with argparse: Scope(use_external_parser=True)

Experiment tracking:

• Track locally in SQLite (zero setup)
• Sync to MLflow/W&B when you need dashboards
• Or use both: local SQLite + cloud tracking

Hyperparameter optimization:

• Built-in Hyperband
• Or compose with Optuna/Ray Tune — Ato's configs work with any optimizer

Three Capabilities Other Tools Don't Provide

1. MultiScope — True namespace isolation with independent priority systems
2. manual command — Visualize exact config merge order for debugging
3. Structural hashing — Track when experiment architecture changes, not just values

When to Use Ato

Use Ato when:

• You want zero boilerplate config management
• You need to debug why a config value isn't what you expect
• You're working on multi-team projects with namespace conflicts
• You want local-first experiment tracking
• You're migrating between config/tracking systems

Ato works alongside:

• Hydra (config composition)
• MLflow/W&B (cloud tracking)
• Optuna/Ray Tune (advanced hyperparameter search)
• PyTorch/TensorFlow/JAX (any ML framework)

---

Roadmap

Ato's design constraint is structural neutrality — adding capabilities without creating dependencies.

Planned: Local Dashboard (Optional Module)

A lightweight HTML dashboard for teams that want visual exploration without committing to cloud platforms:

What it adds:

• Metric comparison & trends (read-only view of SQLite data)
• Run history & artifact browsing
• Config diff visualization
• Interactive hyperparameter analysis

Design constraints:

• No hard dependency — Ato core works 100% without the dashboard
• Separate process — doesn't block or modify runs
• Zero lock-in — delete it anytime, training code doesn't change
• Composable — use alongside MLflow/W&B

Guiding principle: Ato remains a set of independent, composable tools — not a platform you commit to.

---

License

MIT License