fips.Constant#

class fips.Constant(*, within=None)[source]#

Bases: _Kernel

A correlation of one between every two labels (of a group, with within).

Parameters:: within (str | Sequence[str] | None) – Correlate only labels that are the same on these levels; labels of different groups are independent. "level.attribute" groups by an attribute of a datetime level ("obs_time.date").

Examples

Errors shared by every observation of a site on one day:

>>> import pandas as pd
>>> from fips import Constant, Space
>>> times = pd.to_datetime(
...     ["2024-01-01 10:00", "2024-01-01 14:00", "2024-01-02 10:00"]
... )
>>> obs = pd.MultiIndex.from_product([["A"], times], names=["site", "obs_time"])
>>> model = Constant(within=["site", "obs_time.date"])
>>> model.with_std(1.0).build(Space({"co2": obs})).dense()
array([[1., 1., 0.],
       [1., 1., 0.],
       [0., 0., 1.]])

Attributes

`levels`	No levels, since the correlation is one at any distance.
`within`	The levels on which two labels must be the same to be correlated (`"time.hour"` is an attribute of a datetime level).

Methods

correlation(coords)

Return the correlation between the rows of coords, zero between groups (see CorrelationModel.correlation()).

Inherited

From CorrelationModel: with_std