Yeah, a "100% correct" Sudoku solver fully trained by gradient descent from examples? That sure would be something entirely new. To answer dwa3592, it's always

Yeah, a "100% correct" Sudoku solver fully trained by gradient descent from examples? That sure would be something entirely new. To answer dwa3592, it's always possible to set the weights of a neural net by hand, albeit extremely fiddly and normally only done "on paper". This is e.g. how the Turing-completeness of RNNs was shown back in the '90s: On the computational power of neural nets https://binds.cs.umass.edu/papers/1992_Siegelmann_COLT.pdf https://binds.cs.umass.edu/papers/1992_Siegelmann_COLT.pdf