[Ooo-imath-general] preferred way to extend units.imath

[Bill E. <bi...@cr...>]

I wanted to add some more units to my configuration (km, MHz, GHz). My 
iMath extension is installed in (Ubuntu Linux 16.04)
     /usr/lib/libreoffice/share/extension/

In the "imath" directory I found a units.imath file that I edited to 
contain the extra unit definitions. The definition for kilometers is
     %%ii UNITDEF{"km", %km = 10^3 %metre}

But saving my km defition had no effect in iMath. I also tried to edit 
the units.imath file embedded in the oxt file in the install directory. 
No effect.

So then I just pulled out my definitions and dropped them into a new 
file (myunits.imath) and in iMath...Document Options I selected this 
file (myunits.imath). Success!

So I've found one way to accomplish having my own units, but I'm 
wondering if this is the preferred way.

In a similar vein, I'm also curious where I should store physical 
constants (such as speed of light, Planck's constant, etc)?

Bill Eaton
Thousand Oaks, California