Address SettingWithCopyWarning (HMASynthesizer)

[npatki]

Environment Details

• SDV version: 1.4.0 (latest)
• Python version: 3.10
• Operating System: Linux (Google Colab)

Error Description

When sampling from the HMASynthesizer, I receive a SettingWithCopyWarning that is coming directly from pandas. We should update the code based on the pandas recommendations.

Steps to reproduce

from sdv.datasets.demo import download_demo
from sdv.multi_table import HMASynthesizer

real_data, metadata = download_demo(
    modality='multi_table',
    dataset_name='fake_hotels'
)

synthesizer = HMASynthesizer(metadata)
synthesizer.fit(real_data)
synthetic_data = synthesizer.sample(scale=2)

Output:

/usr/local/lib/python3.10/dist-packages/sdv/sampling/hierarchical_sampler.py:107: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead

See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy
  sampled_rows[foreign_key] = parent_row[parent_key]

[npatki]

Confirming that this is also happening on the latest SDV, v1.6.0 that was just released today.

[pvk-developer]

@npatki I was not able to replicate it on this google colab could you share more details about your environment / colab notebook to replicate this?

[npatki]

@pvk-developer you're right. I'm also unable to replicate now. Perhaps Google Colab updated some of its dependencies.

Though wonder if we could address the caveats that pandas is showing us? The message seemed to indicate this link had more info: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy

If we aren't following the recommended practice, we should probably update it anyways.