# HemoGloben

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1. ## Fast way to generate random point on hemisphere?

Quote:Original post by TheAdmiral Picking an arbitrary vector (uniform in 3-space) and normalising it will not give a uniform distribution over the sphere. The density at (1, 1, 1) will be more than that at (1, 0, 0) by a factor sqrt(3). .... Regards Admiral I don't want to derail the discussion, but I think that's really interesting. I can almost see it, but can you explain it a bit more?
2. ## It's the most wonderful time of the year

I've been looking at the mail in thing for a while. Well, actually I've been looking at getting an iPod, and your update pretty much cemented it. Well, anyway, what I'm thinking of doing, is dropping 200 into envelopes and stamps, and mailing it in, provided that it's roughly $1 per envelope, I should end up with a little extra cash. Is it about$1 an envelope? And more importantly, do I have to mail the SASE in another envelope?(Now that I type that out, seems like a stupid question.) Anyway, not that you have to help out the competition, but it sure would be nice to get some 'free' iTunes credit... Thanks.
3. ## Solving Systems of Equations

Off-Topic: ... ... That...was awesome. ...No....really. If my math teacher seemed half as able as you, and delivered his lecture with half the clarity, I probably would've gotten Calculus a heck of a lot sooner. Rating++ for adeptness, managing to stuff a probably very difficult topic into a dummy friendly manner(for the most part anyway), and for not coming off as high/mighty/a dick/pretentious or any of the other thousand words to describe people who do it in such a manner. I'd give you even more for being british, because you have a sense of humor too. Honestly, I'm impressed.
4. ## Solving Systems of Equations

So you have some unknown equation that has given you 100 points. Each point has 41...variables(?)[20 "[letter]", 20"[letter(power)]", and 1 N]? And you're trying to figure out if you knew the equation, would it be solvable? And if it is, is there some way of getting a rough estimate of that equation? EDIT:^^...what he said^^ :-)

Quote:Original post by Iftah (medium) write the robots algo riddle: on an exploration to some line shaped planet, two robots land on the straight 1d line (east/west). Where they land exactly no one knows, but they leave their parachute and landing gear at that point of landing. The robots must meet to start their mission and here is the problem - they don't know which way to go. They can't look far or communicate. Write an pseudo code algorithm to the robots that will result in 100% meeting of the robots. You can use "if" statments and loops and the commands "east" or "west" which moves the robot one step in that direction but you may NOT use variables. You also have the boolean sensors "isNearLandingGear" which means you enter a square with the landing gear and "isNearRobot" which means you win. edit: I tried to add a story but this is not an actual physical simulation... the movement is on a descrete 1d grid and in descrete time intervals (say 1second ticks where both robots move). imagine the "planet" as the integer numbers (west to smaller numbers, east for bigger numbers). For example robot A lands on number 78 and robot B lands on number -16. They leave the parachute right there and it stays there forever. Then they run the algorithm which is some loop (or else it will be finite...) so the loop code will tell them which way to go and such. The simple solution would be to search some radius west and then search the radius east, and increase the radius after such search fails, but you can't use variables so this method can't work. Both robots move 1 step at the same time, but you can assume they will get an "interrupt" and stop the code if they touch (say if one is on number 1 going east and the other on number 2 going west then they will both stop in the middle - no need worrying about them passing eachother). Is the 'line planet' infinite? Or does it wrap around in some way. If it's infinite, I fail to see any solution that gives them 100% chance of meeting.
6. ## [4E5] Screenshots and Art

Render the minimap once, then every time you change a tile, having the change tile function change the corresponding pixel color on the minimap, or maybe set up a queue of pixels to change next frame.
7. ## Recommended High-Performance Workstation CPU (AMD - Intel) Present-2006

From what I hear, the new Mac 64-bit quad workstations are pretty damned fast. Though the video card is a bit weak for something so strong everywhere else. Upgrading should help. As soon as Mac gets all the Boot Camp/Rosetta stuff worked out for it, you should be good to go. Plus, two operating systems has to be better than one. And you can probably install a linux variant on it. My 2 cents.
8. ## OpenGL Trying to project a cube to an specific position.

Are you trying for Orthogonal projection(Not sure if that's the word I'm searching for), like floor plans? Where Instead of the regular view: _ - _ - - | <--Camera O <--Object - _ - _ - You have: ----------------- | |<--Camera 0<--Object | ----------------- ? If so, glOrtho() should help. Along with this page. If not, not sure what you're asking.
9. ## Health bars and such

"healthpercent = playermaxhealth / playerhealth;" Shouldn't the percent be, health/maxhealth? Then again, I suppose you're inverting it later with "66 + 890 / healthpercent" ....But doesn't that make it health/(maxhealth*(66+890))?
10. ## UK Vote on smoking ban passes!

I don't see why they don't just ban smoking/non-smoking sections. That way buisnesses are forced to choose smoking or non-smoking, and you'll know before you go in what you're in for. I smoke, but I understand that people don't like it. I eat and smoke, but understand that it's sort of an anomally among even smokers. But all in all, I live in the USA, and shouldn't it be my right to own a diner where smoking is fully allowed? Sure it may be a poor buisness decision with all the non-smokers nowadays, but still.
11. ## When does an algorithm turn alive?

Quote:Despite our lack of knowledge regarding how humans navigate through mazes... To be fair, humans aren't really competent at navigating mazes. We're a tad to relative, a tad too stuck in the here and now. Which is why I'd say we have so much trouble emulating, ourselves. We've somehow evolved with such a here, now mentality, but are somehow capable of there, then thought. Which is quite a large contradiction, but I've come to think of it as quite accurate. All of our senses are good at relative sensing rather than absolute sensing. Hotter, colder, softer, louder, harder, faster, slower. The only sense mildly absolute is sight, and even that is quite shoddy with absolutes. But I digress.
12. ## When does an algorithm turn alive?

Well first off, I'm glad that the actual of intent of my statements, and their implications was noticed. Sneftel Quote:Seems a little weak. Are you saying that things cannot be alive unless they are comprised of parts which are alive? That seems to break down. Carbon and hydrogen atoms can't really be said to be alive. Concurrently, humans display much more capability for adaptation and intelligence than the cells of which they are composed. They can, by some measure of "alive", be said to be MORE alive than those cells: they display traits above those which the cells themselves can "run". Touche I suppose. Though my statement was really only intended to be an occum's razor of sorts. Then again, we are arguing when systems become humanistic, so trying to deduce when humans become humanistic is probably a pretty good place to start. NQ Quote:I'm having trouble giving examples of complex systems - like France - which are not run by living beings, so I cannot counter the argument. I'd say, that in large part, you're having trouble because there aren't any. Well, outside of humans themselves, which brings us back to arguing about when humans become humanistic.
13. ## When does an algorithm turn alive?

Uhh...Isn't a more likely option to the whole internet seemingly alive, france being alive thing the fact that both happen to be in large part run by humans that are alive? I mean, ...meh. Ok, focus on the france thing. It acts like a living entity because it's run by living entities. Doesn't that make more sense than trying to pretend that france itself is a living entity? Your entire thought experiment attempts to grapple the idea of seperating acts like an entity and is an entity, but somehow manages to miss acts like entity because it's run by entity. Meh, again. I apologize for the incoherence, but I think my general thought is there.
14. ## Dover Publication Books?

I'm actually a senior at high school, trying to learn more advanced math. I know the books aren't meant for me(a lot of them are meant for juniors in college and such), but I really want to learn. I'm most afraid of not getting the terminology and stuff(though not so much, thanks to Wikipedia and mathworld.) I wanted to pick up the book on Modern Algebra, but I ended up getting "Geometry: A comprehensive course". At the moment, it's slow going, only about 6 pages in or so. I keep getting stuck on small technical details, or the descriptions and definitions of things, but it isn't too bad. I'm in AP Calculus BC at the moment. But I'm really just looking into all things math. I love math for math's sake, Pure or Applied, the problem is, I don't quite know where to start. So I figured I'd go through Geometry(I wa shorrible at it the first time around, so I needed to brush up on it anyway), then Algebra. Once those were done, I'd move into Number/Group/Set/Graph Theory and such. Any tips?
15. ## Dover Publication Books?

I'm looking for some good math books, and in browing around book stores, I've found a recurring set of books, namely by Dover Publications. Looking through them, they look like really good books, but the math is for the most part beyond what I know at the moment, so I can't say for certain if they're great books or not. Anyone have any opinions on them? If not, what other math specific lines of books could I/ should I look into?