What are Tensors? - Democratic Underground

UndertheOcean

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Tue Apr-08-08 08:22 PM
Original message

What are Tensors?

Can anyone give me a quick intro ?

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ghostsofgiants

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Tue Apr-08-08 08:24 PM
Response to Original message

1. The only Tensors I know are skateboard trucks.

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pokerfan

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Tue Apr-08-08 08:35 PM
Response to Original message

2. basically a fancy word for an array of numbers

A scalar has one number, right? A vector has magnitude as well as direction. To describe an orbiting body you need a bunch of numbers: three to describe it's location in three space, three to describe its vector velocity.

These are all "tensors" of different class.

There's actually a pretty good wiki article.
http://en.wikipedia.org/wiki/Tensor

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UndertheOcean

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Tue Apr-08-08 08:38 PM
Response to Reply #2

3. What is the relation between tensors and N-dimensional vectors

For example can we say that a Matrix is a Tensor ?

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pokerfan

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Tue Apr-08-08 08:45 PM
Response to Reply #3

4. Yeah

Edited on Tue Apr-08-08 08:46 PM by pokerfan

Same way that a scalar quantity is a tensor of rank 0. Vectors are class 1.

http://en.wikipedia.org/wiki/Tensor#Tensor_rank

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Lethe

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Tue Apr-08-08 09:35 PM
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5. Tensor is the surname of a famous wizard in D&D

who got teased a whole lot as a kid, being really nerdy and scrawny as he was.....

then, as a mighty wizard he crafted a spell that could turn him into a crazy buff fighter, and spent the rest of his days smiting those who mocked him with his mighty broad sword +3

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UndertheOcean

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Tue Apr-08-08 09:41 PM
Response to Reply #5

6. ??

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Lethe

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Tue Apr-08-08 10:04 PM
Response to Reply #6

7. it's true dude

the spell is called Tensor's Transformation

i think he also had a few other ones that summoned a floating disc or something....

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Orrex

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Wed Apr-09-08 09:55 PM
Response to Reply #5

8. That's "Tenser," you faux geek

Tenser

Get your nerdisms right, would you?

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Orrex

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Wed Apr-09-08 09:55 PM
Response to Original message

9. That's when you have boo-boos on each of your toes

Ouch ouch ouch ouch ouch ouch ouch ouch ouch ouch!

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Lionel Mandrake

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Wed Apr-09-08 10:18 PM
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10. It depends on the context.

Engineers deal with stress and strain, which are tensors. The stress tensor makes sense etymologically (tension is a kind of stress). Physicists have their electromagnetic-field and energy-momentum tensors, and Einstein's general theory of relativity is formulated in terms of tensors. All the "tensors" I have mentioned so far are really tensor fields, i.e., they depend on position and maybe on time. There is also an algebraic theory of tensors (not tensor fields) known only to mathematicians.

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UndertheOcean

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Wed Apr-09-08 10:20 PM
Response to Reply #10

11. Any good online introduction other than wikipedia you can point me too

please ?

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Lionel Mandrake

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Wed Apr-09-08 10:40 PM
Response to Reply #11

12. Try these:

Here are just a few web sites about tensors:

http://mathworld.wolfram.com/Tensor.html

http://planetmath.org/encyclopedia/Tensor.html

http://www.math.odu.edu/~jhh/counter2.html

I hope you find what you are looking for.

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UndertheOcean

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Wed Apr-09-08 10:42 PM
Response to Reply #12

13. Thank you

I am planning on studying General Relativity in depth , so mastering Tensors is a must.

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Lionel Mandrake

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Wed Apr-09-08 10:48 PM
Response to Reply #13

15. Good luck (nt)

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madinmaryland

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Wed Apr-09-08 10:44 PM
Response to Original message

14. It's the clenis muscle.

:hide:

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