UNICORN stands for Unit Conversion, is a web application created for resolving the units conversion issues between physics and engineering realms, specifically, in the accelerator system high-level controls field.

The typical use case should be like:

1. The client (script, opi, etc.) got readings from a device, usually from a IOC, say have a variable named current (I), with the value of engineering unit of 10.0 A;
2. The client can ask for the unit interpretation within the physics realm, i.e. What is the significant representation for the accelerator physicist? UNICORN helps.

Let's say the device talking to is FE_MEBT:Q_D1057, which is a quadrupole, by controlling the current (I) the gradient (G) changes. The directly way to do is: firstly locate the function by quick searching, e.g. input 'Q_D1057' in the search box in Functions page, only remaining two entries;

Choose correct function, e.g. 'FE_MEBT:Q_D1057_I_to_G' to convert I to G, Click the function name to direct the detail page, on that page, input {"x":10} in the input box and push run button, the output will be shown in the first two top lines of the function detail page.

The reverse way could be done by picking another function attached to the same device.

As one can see, the web application keeps not only the unit conversion functions, or the scaling laws, but also the data and many other meta properties that could help us organize all the information.

Beside the above way to retrieve the conversion information within the web page, another essential approach is provided by Python package so-called unicorn, REST APIs are served by UNICORN web application, so here is the brief guideline to make the most in the Python scripting environment:

import unicorn
# admin client to UNICORN service
admin_client = unicorn.AdminClient('http://localhost:5000')
# get all functions
admin_client.get()
# get function by name, return a dict
admin_client.get(name='FE_MEBT:Q_D1057_I_to_G')

# api client, the base url + '/api/v1.0'
api_client = unicorn.ApiClient('http://localhost:5000/api/v1.0')

# get function execution result, I --> G
api_client.get('FE_MEBT:Q_D1057_I_to_G', x=10)
# output: {'result': 1.5043739625926702}

# get result from reverse function, i.e. G --> I
api_client.get('FE_MEBT:Q_D1057_G_to_I', x=1.5043739625926702)
# output: {'result': 9.999999999999586}

PPA: The debian package is available in the following PPA:

make env make env_pkg make run

See unicorn.