> SI units are great but sometimes they are not great for the specific use case. When measuring high power systems like power plants or EVs kW/MW/GW are a more appropriate unit versus Watts.
A non-SI example would be e.g. kilowatthours (kWH); since 'hour' is not an SI unit. The SI equivalent would be 3.6 MegaJoules.
> In embedded systems you have limited bandwidth having to have large variables just to store values in SI units is a waste versus using an appropriately scaled unit and saving bandwidth.
- Floats are designed to be scaled, by adjusting their exponents. In the happy case, our algorithms don't care; so why not stick with standard units? In the unhappy case (imprecision, numeric instability) we may need a mixture of entirely bespoke representations, even within a single algorithm. Ideally we'd still use standard units at the "boundaries".
Those are all SI units. In fact, they're all the same unit: the Watt (almost http://www.chriswarbo.net/projects/units/metric_red_herring.... )
A non-SI example would be e.g. kilowatthours (kWH); since 'hour' is not an SI unit. The SI equivalent would be 3.6 MegaJoules.
> In embedded systems you have limited bandwidth having to have large variables just to store values in SI units is a waste versus using an appropriately scaled unit and saving bandwidth.
This seems like a non-issue to me:
- Integer arithmetic can be "appropriately scaled"; we call it https://en.wikipedia.org/wiki/Fixed-point_arithmetic
- Floats are designed to be scaled, by adjusting their exponents. In the happy case, our algorithms don't care; so why not stick with standard units? In the unhappy case (imprecision, numeric instability) we may need a mixture of entirely bespoke representations, even within a single algorithm. Ideally we'd still use standard units at the "boundaries".