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Happy New Year!


(also known as Spartacus)

Project Euler


See those two pins? Well today I'm going to... stick them in you.

Ok, let me come clean: Mr.Wizard is actually an alias of mine... I'm glad I can finally confess. ― Sjoerd C. de Vries

No, I'm Spatac... I mean, Mr.Wizard! ― R.M

I'm Mr.W, and so's my wife! ― acl


@Spartacus, it was not fixable. ― rcollyer

check again; I just fixed it. :-p ― Spartacus


"This is the internet, where the men are men, the women are men and the children are FBI agents..." ― yoda Dec 18 '11 at 6:06


"My main purpose of being here is in collecting the votes. I'd even go further and say that this is my main purpose in life." ― Leonid Shifrin


"I am making some voodoo dance and invoking the rain God while we talk" ― belisarius


Some people are fortunate. Others get married. ― belisarius


It's not that easy to do the untangling even manually though. – Szabolcs

Maybe you could turn it into a puzzle and let other people do the untangling :-) – Heike

I could make a web based game, and feed all my graphs to the visitors.
SE is a big game, isn't it? :D – Szabolcs


"ListContourPlot crush on simple 5-points data" (Question title)

"Yes, this must be love at first sight."ruebenko


... but I am working with a large body of code written by an incompetent fool (i.e. myself, several years ago...) – Simon Woods


I was tempted to edit your title: "Do rules rule?" But my nose is still bleeding as a result of a limerick. – belisarius



50m
comment Replacing a function in defined expressions
If you are not familiar with replacement rules yet that is a good place to start as they are foundational to Mathematica.
50m
comment Replacing a function in defined expressions
@Ismail I'll be glad to try to answer any questions about my code. Basically, any time you create a definition such as func[foo[x_, y_]] := bar[x] + y that rule is added to an internal table. You can recall that rule with e.g. DownValues[func] which should return: {HoldPattern[func[foo[x_, y_]]] :> bar[x] + y}. This list of rules won't behave exactly like the internal definitions but they are usually equivalent. My function simply finds all such rules for every Global symbol, then applies them with ReplaceAll. (continued)
58m
revised Riffle and Partition
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5h
comment Factorisation diagrams
Damn, that's pretty cool. +1
5h
answered Riffle and Partition
12h
revised Efficiently finding the positions of a large list of targets in another, even larger list
edited tags
12h
comment Detecting patterns of black and white stones on a 2D board
Pellesatansfant, Leonid Shifrin has kindly edited this answer to salvage your effort by including a method to allow it to be run from Mathematica. However Sjoerd is entirely correct that answers on this site must focus on Mathematica the software, so please refrain from posting future answers in other languages. Nevertheless thank you for your effort on this one.
12h
revised Detecting patterns of black and white stones on a 2D board
added 6 characters in body
20h
comment Efficiently finding the positions of a large list of targets in another, even larger list
Okay, that didn't make sense. (Nonsense redacted.) I'm overdue for sleep and not thinking clearly. Anyway, thanks for giving me interesting code to chew on. More tomorrow. :-)
20h
comment Efficiently finding the positions of a large list of targets in another, even larger list
It seems to me that the Inner part can be simplified with: Inner[o[[# ;; #2]] &, oo[[;; l]] + 1, oo[[-l ;;]] - 1, List] - l. Also, while I'm still excited about this method, and it is applicable where mine is not, I am finding it somewhat slower than GatherBy as used here (which is what the link lead to). This may be a version difference.
21h
comment Efficiently finding the positions of a large list of targets in another, even larger list
Never mind that last comment; of course it is! :D
21h
comment Efficiently finding the positions of a large list of targets in another, even larger list
I fault you for not posting the general core method by itself, as the superfunction makes it look a lot more hairy than it is, but this is great! Big +1 from me.
22h
comment Removing elements from a list which appear in another list
Is findMultiPos here the same function as findMultiPosXX in the linked post?
22h
comment Removing elements from a list which appear in another list
I haven't yet made the time to read and understand your recent series of related answers but the timings look very impressive. I do feel embarrassed for my answer now however. :-p
22h
revised How does LocationTest choose its “AutomaticTest”?
edited tags
22h
revised Given two samples, how does LocationTest select its AutomaticTest?
edited tags
22h
revised Detecting patterns of black and white stones on a 2D board
deleted 20 characters in body
22h
revised Detecting patterns of black and white stones on a 2D board
correct error
23h
revised Detecting patterns of black and white stones on a 2D board
deleted 288 characters in body
23h
answered Detecting patterns of black and white stones on a 2D board