[FEA] Provide a way to specify the maximum allowable precision for integers/floats

[shwina]

Is your feature request related to a problem? Please describe.

GPU memory is a valuable resource, and using int64/float64 columns where int32/float32 would suffice means using 2x as much memory unnecessarily. As opposed to scientific computing, 32-bit data types (or lower) are sufficient for many data science applications.

Even only 32-bit data types as inputs, the resulting output can be a 64-bit type:

>>> cudf.Series([1, 2, 3], dtype="int32") + cudf.Scalar(1, dtype="float32")
0    2.0
1    3.0
2    4.0
dtype: float64

(this is consistent with Pandas and NumPy)

Describe the solution you'd like

It would be nice to be able to specify a maximum bitwidth for integer/floating types. If an operation would result in a value greater than could be accommodated, simply overflowing would be acceptable.

This could be another use case for cudf.config.

Describe alternatives you've considered

The user can carefully cast results back from 64bit to 32bit to reduce memory usage, but this is tedious and does not help with peak memory usage.

[github-actions]

This issue has been labeled inactive-30d due to no recent activity in the past 30 days. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed. This issue will be labeled inactive-90d if there is no activity in the next 60 days.

[github-actions]

This issue has been labeled inactive-90d due to no recent activity in the past 90 days. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed.