The class UnitSystem in SymPy defines the relations between units. In most cases, the Imperial Units follow the same relations as the SI unit system (maybe there are slight differences in fluid units between the UK and the US?). Anyways, creating an imperial unit system does not make any sense to me, as the SI unit system already implements the relations between imperial units.
New unit systems should be implemented when the relations between units or physical constants are different than in SI. For example, in CGS there is no fundamental unit for electromagnetic quantities, and also physical equations are different from SI. Bear in mind that UnitSystem defines the behaviour of the function "convert_to". You can convert Imperial Units using "convert_to" from SI without any issue (relationships are the same). On the other hand, "convert_to" behaves differently in other unit systems, such as CGS or Natural units. On Thursday, April 25, 2024 at 10:02:04 p.m. UTC+2 Aaron Meurer wrote: > Looking closer, I think you might be right that the imperial system > isn't there. The units are all defined, but there isn't an imperial > Unitsystem that includes them all. This should be straightforward to > add, The main concern I see is that there isn't a single "imperial > system" and what's often called that contains many units that measure > the same quantities. But the SymPy unit systems define a single unit > for each quantity. So we may need to add multiple "systems" to > represent the imperial units. > > Aaron Meurer > > On Thu, Apr 25, 2024 at 1:56 PM Aaron Meurer <asme...@gmail.com> wrote: > > > > I believe the imperial system should already be there, but if there's > > anything missing, we should fix that. > > > > Aaron Meurer > > > > On Thu, Apr 25, 2024 at 10:06 AM 'Henrique Miguel Cortes Soares' via > > sympy <sy...@googlegroups.com> wrote: > > > > > > So, should the imperial system be added? If not, what system could we > add then? > > > > > > Henrique Soares > > > > > > On Tuesday, April 23, 2024 at 10:56:47 PM UTC+1 asme...@gmail.com > wrote: > > >> > > >> I would say that new unit systems should be added only if they are > > >> generally used and useful. General improvements to the units module > > >> are always welcome. Francesco is the main maintainer of the units > > >> module, so he would know more details on what needs to be done there. > > >> > > >> Aaron Meurer > > >> > > >> On Tue, Apr 23, 2024 at 3:54 PM 'Henrique Miguel Cortes Soares' via > > >> sympy <sy...@googlegroups.com> wrote: > > >> > > > >> > Hello all, > > >> > > > >> > I've seen in the page > https://github.com/sympy/sympy/wiki/Unit-systems that two of the possible > improvements for the unit systems in SymPy are to define new unit systems > and improving the access to units and dimensions in a given system. > > >> > Me and a friend wanted to give this feature a try, in the context > of a subject of a Computer Science course we are both taking. > > >> > So, I wanted to ask whether the functionality I described is > something worth working on and not yet implemented. > > >> > > > >> > Thank you for your time. > > >> > > > >> > Best regards, > > >> > Henrique Soares > > >> > > > >> > -- > > >> > You received this message because you are subscribed to the Google > Groups "sympy" group. > > >> > To unsubscribe from this group and stop receiving emails from it, > send an email to sympy+un...@googlegroups.com. > > >> > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/c342d6ca-2d5a-4b5e-ac1a-d4e7488a04d7n%40googlegroups.com > . > > > > > > -- > > > You received this message because you are subscribed to the Google > Groups "sympy" group. > > > To unsubscribe from this group and stop receiving emails from it, send > an email to sympy+un...@googlegroups.com. > > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/2b5adfc0-2e33-4ba9-be7f-43eb2a2093c9n%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/adee7bb8-e7e9-4e18-b981-634e66d94759n%40googlegroups.com.
