From Sudoku Solver to Program Synthesis
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From Sudoku Solver to Program Synthesis
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Re: From Sudoku Solver to Program Synthesis
#2TLDR : we use a solver to go from a formal constraint specification to an Ethereum smart contract
So 1. the initial specification is still a formal constraint
2. the domain complexity is low
3. Use well known solvers to generate code in a DSLRe: From Sudoku Solver to Program Synthesis
#3When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough.
Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku.
Sadly once the solver worked, I kinda lost interest.
I hate backtracking myself and it should only be necessary at a certain Sudoku hardness level - every puzzle below that level of hardness should be solvable without backtracking.
Re: From Sudoku Solver to Program Synthesis
#4When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough. Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku. Sadly once the solver work…
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Re: From Sudoku Solver to Program Synthesis
#5When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough. Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku. Sadly once the solver work…
You are absolutely right. Punching "extra holes" in puzzles of certain hardness should make backtracking not as viable. But we'll loose the unique solution property.
Might make it more interesting? And maybe even bias it towards human-abilities. I think intuitively we're better at solving when the possibilities are more than 1 (just a conjecture.)
Re: From Sudoku Solver to Program Synthesis
#6TLDR : we use a solver to go from a formal constraint specification to an Ethereum smart contract So 1. the initial specification is still a formal constraint 2. the domain complexity is low 3. Use well known solvers to generate code in a DSL
This page was just a fun exercise; seems to have missed communicating fully how we use synthesis. My bad.
You are right about about "2." and part of "3.". For "2." yes, the smart contracts are indeed simpler (small code, gas limits, closed systems). So we can skip some major hurdles that more general techniques need -- case in point the FB abstract interpretation framework Sparta here yesterday. For "3." we use Z3 (as should everybody :)!) but the target language for synthesis is Solidity. [ Hope you didn't mean Solidity is a DSL, coz that would be a generous interpretation of that word. ]
The initial spec is another smart contract (call it IN), so code and not a formal constraint. We synthesize another smart contract (call it OUT), such that the combination (IN + OUT) behaves well. See work on synthesizing program inverters for the background ideas (http://saurabh-srivastava.com/pubs/pldi11-pins.pdf)
Re: From Sudoku Solver to Program Synthesis
#7So is this meant to be an advertisement for their product, or are they trying to recruit? Why are they trying to filter for people who can write a sudoku solver?
Re: From Sudoku Solver to Program Synthesis
#8When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough. Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku. Sadly once the solver work…
You are absolutely right. Punching "extra holes" in puzzles of certain hardness should make backtracking not as viable. But we'll loose the unique solution property. Might make it more interesting? And maybe even bias it towards human-abilities. I think intuitively we're better at solving when the possibilities are more than 1 (just a conjecture.)
My soduku solver from ca~10 years back ran the "hardest" soduku puzzles in It's just not that hard of a problem compared to the speed of computers.
Re: From Sudoku Solver to Program Synthesis
#9When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough. Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku. Sadly once the solver work…
You can make it harder by using 16x16, 25x25, 36x36 etc boards, and see how fast you can make it. There are lots of known patterns to allow for elimination of options http://www.sudokuwiki.org/Getting_Started, of different computation complexity relative to each other, and all faster than regular backtracking. So the goal is to find the order at which to apply them for maximum speed and minimal need to backtrack. You can also try to multithread and use GPU, or FPGA if you're nuts.
All that said, it's all still pretty mechanical. So if you're looking for something more inferential, then another game would be better.
Re: From Sudoku Solver to Program Synthesis
#10When I wrote a Sudoku solver I was disappointed to find that backtracking worked maybe too well; that is, I coded in the minimum constraints to follow the rules of the game and then added backtracking and voila, it found solutions quickly enough. Why was I disappointed? Because initially I wanted to write a solver that inferred more, that used the inferences that I made when solving Sudoku. Sadly once the solver work…
My first attempt did no backtracking at all. It would guess randomly, propagate constraints and continue. If it got stuck, it would just start again. The most it ever took to solve a puzzle was 2100 attempts. Sure it wasn't guaranteed to solve a puzzle in finite time, but it worked well enough for something written during one of those endless big-corp conference calls.