CorrelateShift

class of dascore.proc.correlate
inherits from: PatchProcessor, DascoreBaseModel, pydantic.main.BaseModel

CorrelateShift(
    *args ,
    dim: Any ,
    undo_weighting: Any = True,
)-> None

Apply a shift to the patch data to undo correlation in frequency domain.

Also adds the appropriate coordinate prefixed with “lag” and has a datatype of float.

Parameters

Parameter	Description
patch	The input patch
dim	The dimension name that was correlated in the freq. domain.
undo_weighting	If True, also undo the weighting artifact caused by DASCore’s dft weighting. This is done by simply dividing by the coordinate step, and the data units by the coordinate’s units. See dft note for more details.

Note

A product of transforms is a correlation circular over the transformed length, but idft trims a padded transform back to the original length, which drops the most negative lags. Transform with pad=False, or pad first with patch.pad(time="correlate"), as below.

Examples

import dascore as dc
patch = dc.get_example_patch()

# Example 1
# An auto-correlation of the example patch
dft = patch.dft("time", real=True, pad=False)
dft_sq = dft * dft.conj()
idft = dft_sq.idft()
auto_patch = idft.correlate_shift(dim="time")

Methods

Name	Description
check	Refuse a patch which does not carry what the operation needs.
get_metadata	Return metadata with the lag coordinate, and the axis and step.
kernel	Return the data shifted so zero lag is central, divided by the step.
model_copy	Copy the model, dropping cached values the update invalidates.
new	Create new instance with some attributed updated.
correlate_shift	Apply a shift to the patch data to undo correlation in frequency domain.
reconcile	Return metadata or a patch holding the final data; default as is.
run	Run the operation: check, get_metadata, kernel, reconcile, record.