bidicalc
A spreadsheet where formulas also update backwards
In any normal spreadsheet, when you change values that are the input to some formulas, the outputs are automatically updated:
Could it also work the other way? What if you could also change the output, and have the inputs be updated to match the formula?
For the past few months I've been obsessed really curious about this idea. But there were so many questions:
Would it even be possible at all?
Could it work with very complex formulas? With exponents? With advanced math functions like log() , abs() , etc?
, , etc? How would the UX work? In a normal spreadsheet, when you click on a cell that has a formula, you get to change the formula's expression. I would need a way to let the user change either the formula's expression or the cell's numeric value.
What should happen if there are multiple possible solutions? Like in the example above, if you set A3 to 100, should the result be 50/50, 20/80, -10000/10100? When there is a infinite number of possible solutions, how to pick one?
to 100, should the result be 50/50, 20/80, -10000/10100? When there is a infinite number of possible solutions, how to pick one? Could it work with chained formulas? Could I build a long chain of formulas, update the final value and find the matching inputs all the way backwards?
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