Hacker News Reader

Comment by raketenolli | Hacker News Reader

Looks nice, but is there a reason it interprets m^2 * Pa correctly

  ≫ 1 Pa * 2 m^2 / N
    1 Pa × (2 × m^2 / N)
     = 2

but doesn't automatically convert a result to N?

  ≫ 1 Pa * 2 m^2
    1 Pa × 2 × m^2
     = 2 m²·Pa

Same with W, J, s and all their relations.

View on HN

Thank you for the feedback!

Automatic simplification (as opposed to explicit conversion) is a complex topic. There are a few simplifications that are already applied, for example:

  20 L / m^2
   = 0.02 m

You are absolutely right, it'd be nice to have "Pa·m²" be converted to "N" automatically. I've been thinking about simply going through a list of simple, standardized units (SI units like Newton) while trying to convert the result into these simple units. However, notice that this is not always what you want. If someone likes to compute in imperial units, we would rather leave all quantities in imperial units.

you could only apply simplifications that minimised the sum of the absolute value of all the unit exponents. that would be intuitively satisfying, and not require converting imperial to metric (which would leave the exponents unchanged)

Good suggestion, thank you! I was already thinking about some way to measure "perceived complexity" of a physical unit - this sounds like a very good try for such a heuristic.

Reply on news.ycombinator.com