xarray_squeeze_close

PlasmaCalcs.tools.xarray_tools.xarray_dimensions.xarray_squeeze_close(array, dim=None, tol=0.001, *, closeness_as='coords', closeness_name='closeness_{dim}', keep=None, drop=True)

return array but drop redundant dims, with an tolerance when checking equality.

dims are redundant if all values are close along that dim.

Closeness check here is: (array.isel(dim=0)/array).std() <= tol.

(Special case: if array.isel(dim=0) is all 0s, closeness=0 if array is all 0, else inf.)

For each removed dim:

result will just use array.isel(dim=0).

result will add coord ‘closeness_{dim}’ == std(array.isel(dim=0)/array).

This is a much more aggressive version of array.squeeze():

all dims with size 1 are trivially redundant and will be dropped;

but here, additionally, all dims which are redundant in any way will be dropped.

NOTE: performs all closeness checks before dropping any dims.

dim: None, str, or list of strs

if provided, only consider dropping these dims.

tol: number

drops dim with tol >= (array.isel(dim=0)/array).std().

Use tol=0 to only drop dims with exactly 0 variation along them,

i.e., only dims with all(array.isel(dim=0) == array).

closeness_as: ‘coords’, ‘attrs’, or None

where to put information about closeness == pre-squeeze variation along each dim,

for each dim dropped. (closeness = array.isel(dim=0)/array).std())

(smaller is closer.) (always 0 for dims of size 1.)

‘coords’ –> put info in result.coords

‘attrs’ –> put info in result.attrs

None –> do not include closeness values in the result.

closeness_name: str, default ‘closeness_{dim}’

name for closeness info (see closeness_as above for details).

keep: None, str, or list of strs

if provided, do not consider dropping these dims.

(can provide dim or keep, but not both.)

drop: bool

whether to drop coord for size-1 redundant dims.

if False, will keep scalar coord for size-1 redundant dims.

See also: xarray_closeness