@MartinBüttner Not sure if that's what you want, but not allowing cells to be used more than once turns it into one heck of a set cover problem
Like you could have a ton of Ks on the board, but maybe all except one need to be used by other languages and only one of them is the intended CJam one
Ahaha oops yeah. I'm still thinking about it though
As you say it'd make designing interesting, like if you accidentally leave an "and" next to one of the programs people could have "print(20)and a" "print(20)and ab" "print(20)and abc" giving a very large number of unintended programs
But I guess that's only a problem if you say your board has, say, 50 Python snippets
@Sp3000 please come to the Fortnightly challenge which is on data structures.. Since it was your idea, I believe that u would know more about your own idea than anybody else...
Making a neural network
Challenge
As you can see from the title, you are supposed to make a neural network. The task is to identify whether a given picture contains a number using neural networks. I will give a set of pictures with numbers and without numbers. The pictures will be a 8x8 grid li...
@TAbraham It doesn't matter how it's defined, it's just important that it is unambiguous, otherwise we can't tell who wins. One answer may judge things as numbers that another answer disagrees on. There needs to be a way to decide which one wins. You can choose whatever definition you like as long as it can be applied with no doubt
A more flexible definition might include more than one image for each digit, to allow different ways of drawing the same number
To a human being, the number 4 with one pixel more on the tail would still count as a number 4. You need to decide whether you are asking the program to recognise any number 4, or just the particular one you happen to have drawn.
Incidentally, have you checked the license of the image you used before posting it?
If there is no license then you do not have permission to post it to Stack Exchange, since Stack Exchange has a license that says anyone can use what you post. That's why we are not allowed to post things unless we have the authority to share them
If you search for images with a permissive license then you will be able to post them here, provided you comply with the license (for example, some require you give attribution)
Once you are looking at your image results, look around to see if there are any drop down boxes to further refine by things like date, size and license
and in reverse, because I'd probably implement string with a string mode like Befunge and ><>
as long as you're in string mode, each character is pushed a its character code. when you end string mode, all characters pushed are collected in a string, like CJam arrays
@MartinBüttner I find most of my typos are correctly spelled incorrect words. Sometimes not just a single character out, as if the error happens early on in my brain process rather than at the physical typing stage.
@trichoplax lol yeah... well I guess your muscle memory is still trained to type in certain patterns, so if you're a little off you quickly type an entire wrong word. plus, Freudian slips.
@trichoplax regarding your other comment, yes that's probably right. however I think it'll also make it more obvious where the programs are, especially if one or two are easier to find, as that would narrow down the search space significantly. I think allowing overlap will actually put more emphasis on clever board design, which I think is a good thing.
you're not the first one to bring this up though, so I'll definitely consider it ^^
@MartinBüttner I didn't mean it as a positive or negative - where you want to put the balance between cop difficulty and robber difficulty is up to you... I guess the length of programs affects this too, so it might affect which languages are advantaged
Design and Solve a Maze
(this question on hold while the details are ironed out)
Your task is to play the roles of both characters in this scene from Inception. In it, Cobb gives Ariadne a challenge:
You have two minutes to design a maze that takes one minute to solve.
Some liberties wi...
that moment when you get a new submission to your challenge, recognise the name of the author (which is actually quite common), and it actually is a friend of yours back from school.
@Optimizer well it was a joke. that's most certainly not what happened, since he hasn't logged in to any other SE accounts either since. so I guess he's on holiday.
Solve a 2x2 Eigensystem
code-golfmathcomplex-numberslinear-algebra
For those with a little linear algebra background, the challenge is as simple as this: determine the eigenvalues and eigenvectors of a given complex 2x2 matrix. You may skip ahead to The Challenge for I/O details, etc. For those...
Also I took a few seconds to understand since I was initially thinking of "bottom left" as an absolute location. For some of us "down and left" might be more immediately obvious in meaning.
I'm guessing that scoring by number of answers gives a big advantage to people who answer early. If you don't want to just make the most recent answer the current winner, you could weight based on position so early answers are not worth as much
I tried similar weighting on the Meta Regex Golf, but that wasn't very well-balanced
most importantly, I'd like to include an incentive to use fewer pieces in the score.
a) to make people try harder and b) because feersum has a point that once there are enough pieces it's possible to lock the existing pieces into place by making a block that spans the width and the height ... and at that point the challenge will become pretty difficult for all but some esoteric challenges.
(so if I incentivise people to use fewer pieces it'll take longer to get there)
"Your program has to print N, the number of your answer, to STDOUT or closest alternative. It has to be a full program and must not assume a REPL environment."
Hm, maybe a scoring system like 10 + N - number_of_pieces_added per answer? (And scores are just added for all answers)
alternatively, 10 + N - number_of_pieces_add + number_of_disconnected_groups
@trichoplax yeah. I could either just choose the answer with the highest score, or the user with the highest score (and then accept his last or highest-scoring answer)
@feersum maybe it's worth it if you want to take a bullet for the challenge to go on :P
Lady's and Gentleman....my controller : github.com/matovitch/RatLab/tree/master !! Seems to work...not thoroughly tested though. Do whatever you want with it ! :)
Fortnightly Challenge #4 - Data Structures
Join us in the Fortnightly Challenge Chat to work out the details of this challenge!
This is a placeholder post while we work out a list of ideas.
Ideas presented so far:
Submissions make up nodes in a network through which a Controller needs to sen...
@Sp3000 hm, I thought I had written at least one somewhere, but I'll double-check... and now with being able to move pieces I'll actually reconsider it if I did
I think if the challenge is print N, and I've got enough numbers and operators on the board, rearranging's going to allow for a lot of numbers before you're forced to add more
I think a lot of the answer deserve a lot more upvotes, but I guess most of them are not that interesting to look at if you're not participating in the challenge yourself.
@Optimizer I don't understand why you removed your comment completely now.
Making a neural network
Challenge
As you can see from the title, you are supposed to make a neural network. The task is to identify whether a given picture contains a number using neural networks. I will give a set of pictures with numbers and without numbers. The pictures will be a 8x8 grid li...
honestly, I have to agree with xnor. it's still all very vague. people unfamiliar with neural networks will have no idea what to do. also, with only 10 fixed valid patterns, there doesn't seem to be any reason to involve neural networks in the first place. and it's also not clear how much training data there will be.
posing a neural network challenge is pretty tough, and I think you should try getting some experience with simpler challenges first and also participate in some challenges yourself to get a better feeling for the community
@TAbraham someone without previous knowledge about neural networks will probably have no idea whatsoever what he's supposed to do. a little general background plus links for further reading would be helpful.
Your task is to read an image containing a handwritten digit, recognize and print out the digit.
Input: A 28*28 grayscale image, given as a sequence of 784 plain-text numbers from 0 to 255, separated by space. 0 means white and 255 means black.
Output: The recognized digit.
Scoring: I will tes...
@TAbraham Just to reiterate what has already been said, it's always good to start off with smaller challenges (like codegolf.stackexchange.com/q/607/148 was) before moving on to the more complex ones
mostly what I said in my comment that got three stars. I think the challenge is too ambitious to be pulled off without a fair share of experience on PPCG. I'm not sure I could pull it off myself.
@TAbraham I don't have anything to add that is any different
I'd love to see a neural networks question but so far no one has made one
This isn't due to lack of interest, it's just a hard subject to write a good question for
Why don't you suggest neural networks on the Fortnightly Challenge meta post and see if people are interested? I think the one way it might work is as a collaborative project
Also, generally it's easier to write a good answer than a good question (in my opinion)
yes, suggesting it as a theme might be a good idea. but only do this if you're willing to give control over the challenge to the community to some degree (as the person suggesting it, you'll naturally have your say in the challenge, but be prepared that it's going to be a collaborative effort)
I'd second (third?) the suggestion that you start off with simpler things to practise with. By answering a few questions you'll get to learn about what questions you like and what can go wrong with them, which will give you more insight into what to be careful with when you come to write your own questions
@MartinBüttner I've been travelling for a family funeral, so PPCG hasn't been top of my priorities this week. If I hadn't left my computer in sleep mode with a browser tab open on chat, you probably wouldn't have seen me until tomorrow.
@MartinBüttner (With respect to labelling trees) I think your greedy idea is based around the maximum independent set problem, which is NP-hard for a general graph. But you're given that you're operating on trees, so I would expect there to be a linear time solution. Probably too late, but...
Design and Solve a Maze
(this question on hold while the details are ironed out)
Your task is to play the roles of both characters in this scene from Inception. In it, Cobb gives Ariadne a challenge:
You have two minutes to design a maze that takes one minute to solve.
Some liberties wi...
Solve a 2x2 Eigensystem
code-golfmathcomplex-numberslinear-algebra
For those with a little linear algebra background, the challenge is as simple as this: determine the eigenvalues and eigenvectors of a given complex 2x2 matrix. You may skip ahead to The Challenge for I/O details, etc. For those...
Fortnightly Challenge #4 - Data Structures
Join us in the Fortnightly Challenge Chat to work out the details of this challenge!
This is a placeholder post while we work out a list of ideas.
Ideas presented so far:
Submissions make up nodes in a network through which a Controller needs to sen...
Your task is to read an image containing a handwritten digit, recognize and print out the digit.
Input: A 28*28 grayscale image, given as a sequence of 784 plain-text numbers from 0 to 255, separated by space. 0 means white and 255 means black.
Output: The recognized digit.
Scoring: I will tes...
