Calculator: Option to make exponent divisible by 3 (for metric units reading)

[uhliksk]

Problem Statement
When working with metric units it's usefull to see scientific notation with exponent divisible by 3. Number 3,3898e-4 is not as clear as 338.98e-6 is clearly 338.98µ units.

Evidence or User Insights
You can try "1/2950=" in standard or scientific mode to see result. It was discussed in #226 also.

Proposal
For calculations in metric units it's better to see results in format similar to T, G, M, k, m, µ, n, etc. units.

Goals
User should be able to set exponent divider to make scientific notation easily readable. Default value should by 1 to preserve actual state with ability to enable predefined value 3 (or even other value) to read metric results more easily.

Non-Goals
It's not meant to make any kind of units conversion.

Low-Fidelity Concept
If exp>0 then exp=int(exp/div)div
if exp<0 then exp=int((exp-div+1)/div)div

Requested Assignment
If possible, I would like to implement this.

[MicrosoftIssueBot]

This is your friendly Microsoft Issue Bot. I've seen this issue come in and have gone to tell a human about it.

[msftbot[bot]]

This pitch looks like it has everything it needs for review. In the meantime, we'll keep this idea open for discussion so the community has the chance to provide feedback. Check out our New Feedback Process for more info on the user-centered process we follow for new feature development.

[SaprativRay]

Instead of calling it "metric units reading", I think the preferred term for numbers in scientific notation with exponents divisible by 3 is 'engineering notation'. I believe an ENG/SCI toggle button is the most appropriate user interface integration for this feature.

[uhliksk]

Instead of calling it "metric units reading", I think the preferred term for numbers in scientific notation with exponents divisible by 3 is 'engineering notation'. I believe an ENG/SCI toggle button is the most appropriate user interface integration for this feature.

Engineering units are also feets, pounds, etc. which are not using metric system. Better to use MET/SCI toggle.

[msftbot[bot]]

We reviewed the pitch and would love to explore this idea further! The pitch is a great start, but there are still some open questions. I am moving this issue into planning to iron out some of those details and I created calculator-specs/TBD to track progress. A human will follow up with some feedback on your pitch shortly. Keep in mind that not all ideas that make it into the planning phase are guaranteed to make it to release. For more information on next steps, check out our spec workflow.

[grochocki]

Thanks for the idea! It should be pretty straightforward to expose this in Scientific mode, but a couple details to figure out. Some comments:

• Regarding naming, we believe we should move forward with engineering notation.
• We believe the best approach might be updating this display mode UI to be clearer about switching between display modes: automatic (AUTO, default), scientific notation (SCI), and engineering notation (ENG), but are open to other suggestions.

Perhaps we could leverage the pattern we have in Programmer Mode to cycle between modes:

• This change may make it easier to address #226 (if we go with the approach above, and can introduce a 4th display mode that turns off auto).

[MovGP0]

It's called Engineering Notation and often abbreviated ENG mode on calculators.

Usually there is the option between standard notation (showing integer values for lower values), scientific notation (one digit before the comma) and engineering notation (up to three digits before the comma). Here is an example from the HP Prime calculator:

[ghost]

Engineering Notation from Wikipedia:

Engineering notation (often named "ENG" display mode on scientific calculators) differs from normalized scientific notation in that the exponent n is restricted to multiples of 3. Consequently, the absolute value of m is in the range 1 ≤ |m| < 1000, rather than 1 ≤ |m| < 10. Though similar in concept, engineering notation is rarely called scientific notation. Engineering notation allows the numbers to explicitly match their corresponding SI prefixes, which facilitates reading and oral communication. For example, 12.5×10−9 m can be read as "twelve-point-five nanometres" and written as 12.5 nm, while its scientific notation equivalent 1.25×10−8 m would likely be read out as "one-point-two-five times ten-to-the-negative-eight metres".