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Show HN: I made a spreadsheet where formulas also update backwards
101–110 of 122 posts
Re: Show HN: I made a spreadsheet where formulas also update backwards
#102amazing
Re: Show HN: I made a spreadsheet where formulas also update backwards
#103The interesting thing here isn’t “spreadsheet, but backwards” so much as “spreadsheet as a constraint system”. Classic spreadsheets are basically DAGs: data flows one way and a lot of UX assumptions (and people’s intuition) rely on that. As soon as you allow arbitrary cells to be solved for, you’re in “which variables are free?” land, and most of the confusion in this thread is really about degrees of freedom, not about the math.
One way to make this less surprising might be to flip the default: treat all cells as fixed unless explicitly marked as solver variables, and give a lightweight visualization of “these are the cells that will move if you edit this one.” That keeps the power of a general constraint solver while preserving the mental model spreadsheet users already have, and it opens the door to more serious use cases (financial models, physics, scheduling) without feeling like spooky action at a distance.
Re: Show HN: I made a spreadsheet where formulas also update backwards
#104The interesting thing here isn’t “spreadsheet, but backwards” so much as “spreadsheet as a constraint system”. Classic spreadsheets are basically DAGs: data flows one way and a lot of UX assumptions (and people’s intuition) rely on that. As soon as you allow arbitrary cells to be solved for, you’re in “which variables are free?” land, and most of the confusion in this thread is really about degrees of freedom, not ab…
That's great feedback, thanks! I agree with you, but I don't want to flip the default because this is an experiment I made for fun, and the whole point is to lean in to the chaos a little bit. In a serious product the UX would definitely need a lot more work though.
Re: Show HN: I made a spreadsheet where formulas also update backwards
#105Somebody did this back in the DOS era. The program was sometimes called "the crooked accountant's spreadsheet", because you could start with the outputs you wanted and get the input numbers adjusted to fit.
Anyone remember?
Re: Show HN: I made a spreadsheet where formulas also update backwards
#106I have wanted one general application of this idea in a spreadsheet. Specifically, I track some of my running, including speed (pace), distance, and time. Under different circumstances, I have exactly two of the three available and I want the third to be computed, but it varies which. I have found it fairly difficult to implement this kind of data entry in Google Spreadsheets and Excel, even know conceptually it's a…
You could create a table with 3 columns: distance, time, pace.
Set the display format for time and pace to "Duration".
Enter these formulas:
distance = time / pace
time = distance * pace
pace = time / distance
Re: Show HN: I made a spreadsheet where formulas also update backwards
#107The interesting thing here isn’t “spreadsheet, but backwards” so much as “spreadsheet as a constraint system”. Classic spreadsheets are basically DAGs: data flows one way and a lot of UX assumptions (and people’s intuition) rely on that. As soon as you allow arbitrary cells to be solved for, you’re in “which variables are free?” land, and most of the confusion in this thread is really about degrees of freedom, not ab…
That's great feedback, thanks! I agree with you, but I don't want to flip the default because this is an experiment I made for fun, and the whole point is to lean in to the chaos a little bit. In a serious product the UX would definitely need a lot more work though.
Graphically, I really like the way autodesk makes sketches in fusion 360 blue until they are fully constrained, and then they are black. My intuition here is that you could color code “degrees of freedom” and “locked” states so that it was more intuitive.
Re: Show HN: I made a spreadsheet where formulas also update backwards
#108set A1 = 3 set B1 = 4 set C1 = A1 + B1 = 7 now change C1 = 14 expected A1 = 6 expected B1 = 8 what it did A1 = 7 B1 = 7 great
Why do you think that 6+8 is a better solution than 7+7?
When C1 changes from 7 to 14, that’s a scalar change.
The least-assumption, information-preserving update is to scale both inputs by the same factor.
Re: Show HN: I made a spreadsheet where formulas also update backwards
#109I have wanted one general application of this idea in a spreadsheet. Specifically, I track some of my running, including speed (pace), distance, and time. Under different circumstances, I have exactly two of the three available and I want the third to be computed, but it varies which. I have found it fairly difficult to implement this kind of data entry in Google Spreadsheets and Excel, even know conceptually it's a…
Came here to see if anyone mentioned propagators. That thesis is excellent. I second the recommendation.
Re: Show HN: I made a spreadsheet where formulas also update backwards
#110I have wanted one general application of this idea in a spreadsheet. Specifically, I track some of my running, including speed (pace), distance, and time. Under different circumstances, I have exactly two of the three available and I want the third to be computed, but it varies which. I have found it fairly difficult to implement this kind of data entry in Google Spreadsheets and Excel, even know conceptually it's a…
You just need two spreadsheet tabs. One for the "raw" input and one with a formula that either takes the input if it exists or falls back to the calculated version