Some math equations may break qtassistant

[Gesner Passos]

Add the Dummy.py file at the Code/Mantid/Framework/PythonInterface/plugins/algorithms

Them, from the mantidpath, execute:

 python <MantidCODE>/Code/Mantid/docs/qtassistant/make_algorithms_help.py --latex /usr/bin/latex -m <MantidBuilt>/bin/ -o /tmp --dvipng /usr/bin/dvipng

It will fail with the following error:

...

  File "/apps/mantid/mantid_testing/Code/Mantid/docs/qtassistant/eqnparser.py", line 212, in _compileDVI
    raise RuntimeError("'%s' returned %d" % (" ".join(cmd), retcode))
RuntimeError: '/usr/bin/latex /tmp/html/img/eqn_C_XvWI.tex' returned 1

To solve the problem, you have to change the equations, from

<math>~20%</math>
<math>T^' = 0.158</math>

to

<math>~20</math>%
<math>T^{'} = 0.158</math>

It is not bad that qtassistant breaks. I think it should really break, so we ensure that all the equations will be properly rendered inside the offline help. However, it would be much easier for the developer if we could provide a better description for the failure. My suggest would be provide the text for the equation that broke the builder.

Note that the equations that broke qtassistant are valid inside wiki pages, that is why, I could not easily find why my ​commit related to #6962 broke the builder.

[Gesner Passos]

A do nothing algorithm which is able to break the builder

[Peter Peterson]

Re #7081. Adding more details to failed latex runs.

Changeset: 12febccf0bea975f3d0eec8c540e63baff484755

[Peter Peterson]

Re #7081. Automatically fix un-escaped percent signs.

Changeset: e7686ce857e68f8203395fa94572acb33b925442

[Peter Peterson]

Re #7081. Added automatic replacement for prime character.

Changeset: bf2924d28b0d6b13e1952d1e315ca3906d20bda4

[Peter Peterson]

This is in ​bugfix/7081_qtassistant_error_reporting.

To test:

1. Put the attached "Dummy.py" into Code/Mantid/Framework/PythonInterface/plugins/algorithms as suggested
2. make qtassistant target

Also, look at the changes to the code to see that there is more information when this fails.

[Wenduo Zhou]

Line 129: raise RuntimeError("latex executable ('%s') does not exist. (%s), " % LATEX)

Variable "LATEX" is not defined. Ticket is reopened by this reason.

[Peter Peterson]

Re #7081. Fixed bug in error messages of eqnparser.

Changeset: 555980936a73012339bb6f59b106572306496e0a

[Peter Peterson]

Should be all good now. Same instructions as comment:5

[Wenduo Zhou]

The errors have been corrected. Thus the ticket is closed.

[Anders Markvardsen]

add first SmyS instrument. re #7081

Changeset: daefc0ae726c8a1204b063e7de74541eaeda0adb

[Anders Markvardsen]

Apologizes put comment above to wrong ticket should have been #7087

[Stuart Campbell]

This ticket has been transferred to github issue ​7927