quacc

1.2.6 verified Sat May 09 auth: no python

A platform for high-throughput, database-driven quantum chemistry and computational materials science. Current version: 1.2.6. Release cadence: monthly.

pip install quacc

Common errors

error ModuleNotFoundError: No module named 'quacc' ↓

cause quacc requires Python >=3.11

fix

Upgrade Python to 3.11 or higher, then pip install quacc

error AttributeError: module 'quacc' has no attribute 'Flow' ↓

cause Importing from the wrong location or using an older version

fix

Use from quacc import Flow (not from quacc.flow import Flow). Upgrade to >=1.0.

error ValueError: Unknown recipe decorator ↓

cause The @recipe decorator was introduced in v1.2.0

fix

Upgrade quacc to >=1.2.0: pip install --upgrade quacc

Warnings

breaking In v1.0, the database backend was changed from SQLite to a custom JSON-based store. Existing databases are not compatible. ↓

fix Export your old data using quacc<1.0 and re-import with quacc>=1.0.

gotcha The QUACC_DB_FILE environment variable must be set before importing quacc, otherwise a temporary file is used. ↓

fix Set os.environ['QUACC_DB_FILE'] = 'my_db.json' before importing quacc.

deprecated The quacc.database module is deprecated in favor of top-level functions. ↓

fix Use from quacc import get, put instead of from quacc.database import get, put.

Imports

Flow
wrong
```
from quacc.flow import Flow
```
correct
```
from quacc import Flow
```
Flow is re-exported from the top-level package since v1.0
get
wrong
```
from quacc.database import get
```
correct
```
from quacc import get
```
get is available at top level to simplify usage
quacc
wrong
```
import quacc as qc
```
correct
```
import quacc
```
Common but not necessary; top-level API is designed to be small

Quickstart

Basic usage: define a recipe and run it in a Flow.

import os
os.environ['QUACC_DB_FILE'] = os.environ.get('QUACC_DB_FILE', 'quacc.db')
from quacc import Flow, get, recipe

# Define a simple relaxation workflow
@recipe
def relax(atoms, calculator):
    atoms.calc = calculator
    atoms.get_potential_energy()
    return atoms

# Run the flow
flow = Flow()
flow.add(relax, atoms=...)
flow.run()