Vietnamese math teacher's puzzle!

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Permalink Reply by David Rutten on June 3, 2015 at 1:01am

Jitter is not a good variable to modify. It is discontinuous and gives no guarantee that all possible permutations are accessible. But then the whole problem is totally discontinuous so Galapagos is not a good tool for solving it. It basically comes down to a brute force search that doesn't even search the entire solution space, which has a size of 9! by the way which equals 362880.

Since Galapagos assumes every problem you give it is at least a little continuous, it will get stuck at 'near 66' states, which probably doesn't help much.

If the problem however has more than one solution, then there's no way of telling which one galapagos will find.

Permalink Reply by Riccardo Majewski on June 3, 2015 at 3:42am

And here it is!

If I haven't done wrong, there are 136 possible combinations that give out 66.

Btw 80 seconds of calculation!! (enable cross product component and wait... patiently...)

(man... brute force sucks! ... or not? ... I would like to know GPGPU/OpenGL + c# to try a multi-parallelized version ... but I have no clue T_T )

This def is not adaptive, so with a new problem, other than rewrite the formula you'll have to readapt the components manually.... (i suggest to do that with CrossProduct component disabled)

:D

Permalink Reply by Riccardo Majewski on June 3, 2015 at 3:43am

attachment :P

Permalink Reply by Riccardo Majewski on June 3, 2015 at 3:44am

duh

Attachments:

• script.gh, 18 KB

Permalink Reply by David Rutten on June 3, 2015 at 3:53am

If you're going to try and solve this with a brute force method, you'll have to set it up so that all possible states can indeed be handled. I also think you had your precedence brackets set up wrong. I'm not sure if the puzzle uses proper operator precedence (in which case no brackets are needed) or if all operations are simply meant to be taken in turn. I assumed the latter.

Attachments:

• puzzle.gh, 8 KB

Permalink Reply by Riccardo Majewski on June 3, 2015 at 4:09am

This is lighter!

If as you say, David, there are 1305 solutions...

Btw in the solution page here: http://www.theguardian.com/science/alexs-adventures-in-numberland/2... they set it up as Daniel's formula...

...Why formatted text TO int weight way lesser than evaluating an expression??

Attachments:

• puzzle_V2.gh, 16 KB

Permalink Reply by David Rutten on June 3, 2015 at 5:16am

text -> int actually does evaluate the expression as well, so it's not faster.