When Nexus contains the correct param map don't try load external param file

[Anders Markvardsen]

With conversation with Martyn

When ISIS/SNS raw Nexus fils contains param map don't try load external param file.

This should make no difference to SNS since it is believed that SNS do not include param map in Nexus file.

But it will work better for ISIS where a valid param map is shipped with the raw Nexus file

Put as critical, since at ISIS this is causing considerable confusion, when instrument scientist is hoping to work with the parameters contained within the nexus file but finds that these have been overwritten by different values upon load

[Anders Markvardsen]

From discussions with Alex he has pointed out a valid point, which at least I had not really registered. That is there is an advantage of have external IDF and parameter files over internal once in that the former can be modified retrospective and ensure that new releases of Mantid are shipped with backward competable such files.... Hence based on this I would be useful if we could have a transparent mechanism for automatically overwrite wrongly embedded IDF and parameter information in a Nexus, hopefully this will only happen rarely, but it will happen

[Anders Markvardsen]

For information.

The order at which Load handle ISIS/SNS Nexus files with an embedded IDF at the moment is (from the point of view IDF and instrument parameters):

1. Load embedded IDF, including any instrument parameters defined in this file. These instrument parameters are then applied after the log files have been read in - in order to handle the <logfile> instrument parameter file entries like:

<parameter name="x">

<logfile id="trolley2_x_displacement" extract-single-value-as="position 1" />

</parameter>

2. For ISIS raw Nexus file only, I believe, the Nexus file may also contain an entry instrument->instrument_parameter_map entry which is a text string format version of a parameter map contained in workspace (identical to those we store for processes mantid nexus files)

If exist this parameter map gets applied to the workspace after step 1

3. Say the instrument is LET, then Load will look for LET_Parameters.xml and if exist apply the parameters in this file

[Anders Markvardsen]

note in connection with this ticket the tread ​​https://github.com/mantidproject/documents/blob/master/Design/EmbeddedInstrumentInfoNexus.md has been created

[Anders Markvardsen]

don't load 'fallback' parameter file if map in nexus. re #9467

Change the behaviour of LoadIDFFromNexus and before doing this, as part of trying to ensure I wasn't broking something, updated various code comments related to loading of xml files

Changeset: f1865b55a3de41be8505985ca7b48cea7cc533b9

[Anders Markvardsen]

To test e.g. do:

1. load HYSA_12509.nxs.h5 in AutoTestData which contains an embedded IDF. When loading it you should get the log message: "Instrument parameter file: C:/Backup/Backup_folder1/work/code/Mantid/git/mantid/Code/Mantid/instrument/HYSPECA_Parameters.xml has been loaded"

2. Load MAPS00018314.nxs in systemtest/data (recently added with #8214). When loaded you should get the message: "Found Instrument parameter map entry in Nexus file, which is loaded"

[Anders Markvardsen]

Updated alg doc so it reflect what is done in code. re #9467

Changeset: 0aa2ccf4882c2d86d787fe54294f56a5828b6aac

[Anders Markvardsen]

To tester: see comment 10

[Alex Buts]

Merge remote-tracking branch 'origin/feature/9467_if_param_map_in_nexus'

Full changeset: ​781eca6cc7b69625d9d40dc0b409d4a2e0ad0a47

[Alex Buts]

works as described and fine as first step of changes outlined in ​https://github.com/mantidproject/documents/blob/master/Design/EmbeddedInstrumentInfoNexus.md

[Stuart Campbell]

This ticket has been transferred to github issue ​10310