Track ML experiments with automatic logging, visualize training in real-time, optimize hyperparameters with sweeps, and manage model registry with W&B - collaborative MLOps platform
# Install W&B
pip install wandb
# Login (creates API key)
wandb login
# Or set API key programmatically
export WANDB_API_KEY=your_api_key_here
Quick Start
Basic Experiment Tracking
import wandb
# Initialize a run
run = wandb.init(
project="my-project",
config={
"learning_rate": 0.001,
"epochs": 10,
"batch_size": 32,
"architecture": "ResNet50"
}
)
# Training loop
for epoch in range(run.config.epochs):
# Your training code
train_loss = train_epoch()
val_loss = validate()
# Log metrics
wandb.log({
"epoch": epoch,
"train/loss": train_loss,
"val/loss": val_loss,
"train/accuracy": train_acc,
"val/accuracy": val_acc
})
# Finish the run
wandb.finish()
With PyTorch
import torch
import wandb
# Initialize
wandb.init(project="pytorch-demo", config={
"lr": 0.001,
"epochs": 10
})
# Access config
config = wandb.config
# Training loop
for epoch in range(config.epochs):
for batch_idx, (data, target) in enumerate(train_loader):
# Forward pass
output = model(data)
loss = criterion(output, target)
# Backward pass
optimizer.zero_grad()
loss.backward()
optimizer.step()
# Log every 100 batches
if batch_idx % 100 == 0:
wandb.log({
"loss": loss.item(),
"epoch": epoch,
"batch": batch_idx
})
# Save model
torch.save(model.state_dict(), "model.pth")
wandb.save("model.pth") # Upload to W&B
wandb.finish()
Core Concepts
1. Projects and Runs
Project: Collection of related experiments
Run: Single execution of your training script
# Create/use project
run = wandb.init(
project="image-classification",
name="resnet50-experiment-1", # Optional run name
tags=["baseline", "resnet"], # Organize with tags
notes="First baseline run" # Add notes
)
# Each run has unique ID
print(f"Run ID: {run.id}")
print(f"Run URL: {run.url}")
2. Configuration Tracking
Track hyperparameters automatically:
config = {
# Model architecture
"model": "ResNet50",
"pretrained": True,
# Training params
"learning_rate": 0.001,
"batch_size": 32,
"epochs": 50,
"optimizer": "Adam",
# Data params
"dataset": "ImageNet",
"augmentation": "standard"
}
wandb.init(project="my-project", config=config)
# Access config during training
lr = wandb.config.learning_rate
batch_size = wandb.config.batch_size
# Download and use artifact
run = wandb.init(project="my-project")
# Download artifact
artifact = run.use_artifact('training-dataset:latest')
artifact_dir = artifact.download()
# Use the data
data = load_data(f"{artifact_dir}/train.csv")
Model Registry
# Log model as artifact
model_artifact = wandb.Artifact(
name='resnet50-model',
type='model',
metadata={'architecture': 'ResNet50', 'accuracy': 0.95}
)
model_artifact.add_file('model.pth')
wandb.log_artifact(model_artifact, aliases=['best', 'production'])
# Link to model registry
run.link_artifact(model_artifact, 'model-registry/production-models')
wandb.init(
project="my-project",
tags=["baseline", "resnet50", "imagenet"],
group="resnet-experiments", # Group related runs
job_type="train" # Type of job
)
2. Log Everything Relevant
# Log system metrics
wandb.log({
"gpu/util": gpu_utilization,
"gpu/memory": gpu_memory_used,
"cpu/util": cpu_utilization
})
# Log code version
wandb.log({"git_commit": git_commit_hash})
# Log data splits
wandb.log({
"data/train_size": len(train_dataset),
"data/val_size": len(val_dataset)
})