How do I launch multiple runs from one script?

  less than a minute  

Finish previous runs before starting new runs to log multiple runs within a single script.

The recommended way to do this is by using wandb.init() as a context manager because this finishes the run and marks it as failed if your script raises an exception:

import wandb

for x in range(10):
    with wandb.init() as run:
        for y in range(100):
            run.log({"metric": x + y})

You can also call run.finish() explicitly:

import wandb

for x in range(10):
    run = wandb.init()

    try:
        for y in range(100):
            run.log({"metric": x + y})

    except Exception:
        run.finish(exit_code=1)
        raise

    finally:
        run.finish()

Multiple active runs

Starting with wandb 0.19.9, you can set the reinit setting to "allow" to create multiple simultaneously active runs. The recommended way to do this is by calling wandb.setup() after importing wandb.

import wandb

wandb.setup(wandb.Settings(reinit="allow"))

with wandb.init() as tracking_run:
    for x in range(10):
        with wandb.init() as run:
            for y in range(100):
                run.log({"x_plus_y": x + y})

            tracking_run.log({"x": x})

Last modified March 5, 2025: 095cde2