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Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

filiph.github.io

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Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#21

Post by constantcrying »

An alternative approach is using fuzzy-numbers. If evaluated with interval arithmetic you can do very long calculations involving uncertain numbers very fast and with strong mathematical guarantees.

It would especially outperform the Monte-Carlo approach drastically.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#23

Post by constantcrying »

porridgeraisin wrote: post #16
kccqzy wrote: post #5

Earlier quoted context omitted.

Yes it is.

Can you explain how? I'm an (aspiring)

Line 19 to 21 should be the Monte-Carlo sampling algorithm. The implementation is maybe a bit unintuitive but apparently he creates a function from the expression in the calculator, calling that function gives a random value from that function.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#24

Post by constantcrying »

croisillon wrote: post #19

i like it and i skimmed the post but i don't understand why the default example 100 / 4~6 has a median of 20? there is no way of knowing why the range is between 4 and 6

The chance of 4~6 being less than 5 is 50%, the chance of it being greater is also 50%. The median of 100/4~6 has to be 100/5.

>there is no way of knowing why the range is between 4 and 6

??? There is. It is the ~ symbol.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#25

Post by constantcrying »

alexmolas wrote: post #18

is this the same as error propagation? I used to do a lot of that during my physics degree

It doesn't propagate uncertainty through the computation, but rather treats the expression as a single random variable.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#26

Post by re »

vessenes wrote: post #22

cool! are all ranges considered poisson distributions?

No:

> Range is always a normal distribution, with the lower number being two standard deviations below the mean, and the upper number two standard deviations above. Nothing fancier is possible, in terms of input probability distributions.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#28

Post by notfed »

BrandoElFollito wrote: post #9
rogueptr wrote: post #2

brilliant work, polished ui. although sometimes give wrong ranges for equations like 100/1~(200~2000)

How do you process this equation ? 100 divided by something from one to ...?

> 100 / 4~6

Means "100 divided by some number between 4 and 6"

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#29

Post by krick »

It sounds like a gimmick at first, but looks surprisingly useful. I'd surely install it if it was available as an app to use alongside my usual calculator, and while I cannot quite recall a situation when I needed it, it seems very plausible that I'll start finding use cases once I have it bound to some hotkey on my keyboard.

Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator

#30

Post by ttoinou »

Would be nice to retransform the output into an interval / gaussian distribution

   Note: If you're curious why there is a negative number (-5) in the histogram, that's just an inevitable downside of the simplicity of the Unsure Calculator. Without further knowledge, the calculator cannot know that a negative number is impossible
Drake Equation or equation multiplying probabilities can also be seen in log space, where the uncertainty is on the scale of each probability, and the final probability is the product of exponential of the log probabilities. And we wouldnt have this negative issue
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