scippneutron.io.cif.CIF

class scippneutron.io.cif.CIF(name='', *, comment='')

A builder for CIF files.

This class implements a builder pattern for defining the contents of a CIF file. See the module documentation of cif for examples.

__init__(name='', *, comment='')

Methods

__init__([name, comment])
copy()	Return a copy of this builder.
save(fname)
with_authors(*authors)	Add one or more authors.
with_beamline(*, beamline[, facility, ...])	Add beamline information.
with_powder_calibration(cal, *[, comment])	Add a powder calibration table.
with_reduced_powder_data(data, *[, comment])	Add a loop with reduced powder data.
with_reducers(*reducers)	Add one or more programs that were used to reduce the software.

Attributes

comment	Optional comment that can be written at the top of the file.
name
schema	CIF schemas used for the file.

property comment: str

Optional comment that can be written at the top of the file.

copy()

Return a copy of this builder.

Return type:

CIF

save(fname)

Parameters:

fname (str | Path | TextIOBase) – Path or file handle for the output file.

Return type:

None

property schema: set[CIFSchema]

CIF schemas used for the file.

with_authors(*authors)

Add one or more authors.

Parameters:

authors (Author) – Authors to add to this CIF object.

Returns:

CIF – A builder with added calibration data.

with_beamline(*, beamline, facility=None, device=None, comment='')

Add beamline information.

Return type:

CIF

with_powder_calibration(cal, *, comment='')

Add a powder calibration table.

The calibration data encode the following transformation from d-spacing to time-of-flight:

\[t = \sum_{i=0}^N\, c_i d^{p_i}\]

where \(c_i\) is the i-th element of cal and \(p^{p_i}\) is the i-th element of cal.coords['power'].

Parameters:

• cal (DataArray) – The data are the calibration coefficients (possibly with variances). Must have a coordinate called 'power' defining \(p\) in the equation above.

• comment (str, default: '') – Optional comment that can be written above the data in the file.

Returns:

CIF – A builder with added calibration data.

Examples

Add a mockup calibration table:

>>> import scipp as sc
>>> from scippneutron.io import cif
>>> cal = sc.DataArray(
...     sc.array(dims=['cal'], values=[3.4, 0.2]),
...     coords={'power': sc.array(dims=['cal'], values=[0, 1])},
... )
>>> cif_ = cif.CIF('powder-calibration')
>>> cif_ = cif_.with_powder_calibration(cal)

with_reduced_powder_data(data, *, comment='')

Add a loop with reduced powder data.

The input must be 1-dimensional with a dimension name in ('tof', 'dspacing'). The data array may also have a name in ('intensity_net', 'intensity_norm', 'intensity_total'). If the name is not set, it defaults to 'intensity_net'.

The data gets written as intensity along a single coord whose name matches the dimension name. Standard uncertainties are also written if present.

The unit of the coordinate must match the requirement of pdCIF.

Parameters:

• data (DataArray) – 1-dimensional data array with a recognized dimension name

• comment (str, default: '') – Optional comment that can be written above the data in the file.

Returns:

CIF – A builder with added reduced data.

Examples

Make mockup powder diffraction data:

>>> import scipp as sc
>>> tof = sc.array(dims=['tof'], values=[1.2, 1.4, 2.3], unit='us')
>>> intensity = sc.array(
...     dims=['tof'],
...     values=[13.6, 26.0, 9.7],
...     variances=[0.7, 1.1, 0.5],
... )

Add to a CIF builder:

>>> from scippneutron.io import cif
>>> cif_ = cif.CIF('reduced-data')
>>> da = sc.DataArray(intensity, coords={'tof': tof})
>>> cif_ = cif_.with_reduced_powder_data(da)

with_reducers(*reducers)

Add one or more programs that were used to reduce the software.

Parameters:

reducers (str) – Pieces of software that were used to reduce the data. Each string is one piece of software in freeform notation. It is recommended to include the program name and version.

Returns:

CIF – A builder with added calibration data.