propagateDifcal

Overview

It is fequently useful (and sometimes necessary) to copy a diffraction calibration (difcal) from one state to another. This is a valid operation when the donor and destination states have identical detector positions. When provided with the run number of an existing difcal operation, propagateDifcal automatically identifies (existing) compatible states and copies the calibration across, while also updating the calibration indices used by SNAPRed to locate the new calibration.

Note

This utility only works for instrument scientists with write access to the calibration directory

Typical usage would be

import snapwrap.utils as wrap

wrap.propagateDifcal(64431)

If necessary, it is possible to create a new state first, making it available to propage the difcal to. This can be done with a separate module called snapStateMgr which has a function called createState

For example:

import snapwrap.utils as wrap
import snapStateMgr as ssm

ssm.createState(64433) #creates 6.4Å state
snapwrap.propagateDifcal(64431) #propagates an existing calibration made using run 64431 to this state

Optional arguments

isLite

Calibrations are lite/native dependent and must be conducted separately for each mode. Since propagation of a difcal relies on it existing, the corresponding calibration must have been conducted.

By default isLite=True but, if an existing native calibration needs to be transferred, this can be done by specifying isLite=False.

propagate

It is good practice to examine the expected outcome of propagation without actually propagating any data. Consequently, this is the default behaviour and the parameter propagate set equal False.

Once you are sure everything looks good, setting propagate=True will actually propagate the calibration. Once this happens, an entry will be created in the calibration index of the corresponding state and will henceforth be treated as a formal calibration.