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On September 09 2015 01:45 FiWiFaKi wrote:
How do I go about curve fitting a set of points in 3D space? Simply assume I have x,y,z position vectors from t_i, i->n, and want to obtain a continuous function for these discrete set of points so I can do some calculus on it.
Try x=fx(t) with fx(t) that goes through the expected points (same for y and z)
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Is going to a ex girlfriends wedding a good idea?
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On September 09 2015 03:49 whatisthisasheep wrote:
Is going to a ex girlfriends wedding a good idea?
If you still speak and was invited, yes.
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On September 09 2015 03:49 whatisthisasheep wrote:
Is going to a ex girlfriends wedding a good idea?
If you've been clearly invited by said ex-gf (if it's the future husband who invited you make sure your ex is ok with it too) and you know you can behave like a normal guest, yes, of course. If not, avoiding it will probably be the best for everyone involved.
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On September 09 2015 03:49 whatisthisasheep wrote:
Is going to a ex girlfriends wedding a good idea?
Personally I wouldn't but other's have pointed out valid exceptions. That being said I am not on any kind of terms with my exs.
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On September 09 2015 03:49 whatisthisasheep wrote:
Is going to a ex girlfriends wedding a good idea?
If you have to ask--then it's a no.
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On September 09 2015 04:01 OtherWorld wrote:Show nested quote +On September 09 2015 03:49 whatisthisasheep wrote:
Is going to a ex girlfriends wedding a good idea? If you've been clearly invited by said ex-gf (if it's the future husband who invited you make sure your ex is ok with it too) and you know you can behave like a normal guest, yes, of course. If not, avoiding it will probably be the best for everyone involved.
I got a formal wedding invitation in the mail from her, but we haven't really spoken to each other in about a year so. I don't know who the groom will be so I was surprised to be invited.
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In that case, why the fuck would you want to be there? It is a wedding. Weddings aren't fun for anyone. You go because people get angry if you don't. If you don't speak to her, no one you care about will get angry if you go, thus you don't have to go.
On September 09 2015 01:45 FiWiFaKi wrote:
How do I go about curve fitting a set of points in 3D space? Simply assume I have x,y,z position vectors from t_i, i->n, and want to obtain a continuous function for these discrete set of points so I can do some calculus on it.
I have Linear Algebra I, Calc I-III (Differential, Integral, Basic Multivariate), 1 Differential Eqn's + 1 Numerical Methods course in my math repertoire, as well as some self-taught Linear Algebra II from Khan Academy and sprinkles of Calc IV as needed for Engg classes (Stokes, Divergence Theorem, etc).
I don't really know where to begin, the Numerical methods I've done, was always done in 2D... I suppose I'd start with how to define a line in 3D. Now this is not possible with a f(x,y,z)=A type function, since that'll give you a plane. So my initial opinion is to use parametric curves (which essentially no time was spent on in courses). So in 2D, making any explicit function a parametric curve is easy... say x=t, and replace y=f(x) with y=f(t), and you have two equations.
Now I don't really know how you go about parameterizing implicit functions... Like sure, I know x^2+y^2=1 will be x=cos(t) and y=sin(t)... And if you give me the parametric curves, I can get to x^2+y^2, but going the other way is a lot more difficult for me. And then I could add say a z=t^2, and voila... I have a helix that is increasing in pitch with the z-axis.
So I'm thinking that I need to break the function down into x(t) = f(t), fit that curve, y(t) = f(t), fit that, and do it for z as well. So then I can curve fit a nice polynomial or exponential or whatever for it... But then, I don't really know what to do with it, I don't know how to combine it all together. Do I then treat it as a system of 3 equations of t?... How do I operate on it?
So if I am on the right track with the parametric curves to solve my problem, does anyone have any suggestions where to go from here? What mathematics I need to go study (or maybe just revisit some previous math - currently redoing it with Lin Algebra, now that I actually know what kind of problems it can be used for), etc? Or is it a more complex (or less complex) problem than I'm giving it credit for?
If you have the x(t), y(t), z(t), you are done. Write this as a vector and you have a parametrised curve in a 3d space, which i assume is exactly what you wanted as a result to begin with? What kind of operations do you wish to use on it?
You could also fit some sort of plane to your data, but from what you wrote that is explicitly not what you want to do. That would allow you to get something that looks more like a classic fit in 2d, with z as a function of x and y. If you only want to have a curve, you are going to end up with a parametrised version no matter what you do, since you can't write a curve in 3d space as z(x,y) as you mentioned yourself.
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Alternatively, admit that you have a multi-variate regression problem and treat it as such.
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Edit: Apparently i suck at editing and quoted myself instead. Sorry.
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Are police officers in America more interested in generating revenue for their municipalities than actually preventing crime?
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On September 09 2015 05:57 whatisthisasheep wrote:
Are police officers in America more interested in generating revenue for their municipalities than actually preventing crime?
Yes and no. Depends on the region and how they are funded. They do have to write tickets to generate revenue. And some states have privately run prisons, which creates its own set of problems.
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Can I raise a pet dolphin without it living in a source of water? What if I strapped it to a skateboard or something and gave it a way to maneuver itself somehow? That way it could meander through my house, and I could take it out for walks like like a dog and clean up its dolphin poop in little baggies.
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On September 09 2015 11:22 Epishade wrote:
Can I raise a pet dolphin without it living in a source of water? What if I strapped it to a skateboard or something and gave it a way to maneuver itself somehow? That way it could meander through my house, and I could take it out for walks like like a dog and clean up its dolphin poop in little baggies.
I literally can't see any problem with this.
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I invite you to google Margaret Howe for all your "living with a dolphin" questions.
tl:dr: they had sex.
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Why do colleges teach two theory's that directly contradict each other? On the one hand they teach embracing cultural diversity and celebrating the differences between ethical backgrounds. Then they teach that everyone is equaly the same regardless of gender, race, cultural upbringing etc. if we're all the same how do we celebrate differences?
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Zurich15366 Posts
On September 09 2015 15:56 whatisthisasheep wrote:
Why do colleges teach two theory's that directly contradict each other? On the one hand they teach embracing cultural diversity and celebrating the differences between ethical backgrounds. Then they teach that everyone is equaly the same regardless of gender, race, cultural upbringing etc. if we're all the same how do we celebrate differences?
You really can't answer this for yourself?
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On September 09 2015 15:56 whatisthisasheep wrote:
Why do colleges teach two theory's that directly contradict each other? On the one hand they teach embracing cultural diversity and celebrating the differences between ethical backgrounds. Then they teach that everyone is equaly the same regardless of gender, race, cultural upbringing etc. if we're all the same how do we celebrate differences?
I'm assuming you are joking, but I also think that many people would not spot the error in an argument like this against equality and cultural diversity. Especially if you take people that don't want to spot an error, with confirmation bias and all. I think the point here is that it is very easy to twist things into looking like something very different, turning valid arguments into nonsense, and the other way around.
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On September 09 2015 11:22 Epishade wrote:
Can I raise a pet dolphin without it living in a source of water? What if I strapped it to a skateboard or something and gave it a way to maneuver itself somehow? That way it could meander through my house, and I could take it out for walks like like a dog and clean up its dolphin poop in little baggies.
A dolphin needs the water. Even on land it would require its skin to be kept wet. Its fins would not resist trying to propel it on land. My guess is the simple fact of lying on its belly would damage it in the long run. Lastly, it relies heavily on sound to communicate and sense its surroundings (sonar + song) which would not work in open air.
Perhaps some tore of water that rolls as the dolphin moves and creates a water flow in which it swims, with an active system that reads sonar impulses from the dolphin and provides a feedback computed from a real time model of the surroundings based on camera input ? Not practical in a house and the dolphin would still have issues with moving in only 2 dimensions.
Another option is to modify the dolphin DNA so that it can live on land... Not sure the result is still a dolphin.
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I though dolphin were so intelligent. Can't they just adapt themselves?
He could ask you a few tips at start, of course.
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EPT
