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10 Apr 2020
12:32:21@greenturtle:matrix.orggreenturtle * The Weyl tensor should have four 'slots' in its shape. Always. what goes in each slot is the number of dimensions
12:33:34@ritzvik:matrix.orgRitwik Saha Lemme see
12:34:18@greenturtle:matrix.orggreenturtleplease
12:35:10@ritzvik:matrix.orgRitwik Saha
In reply to @ritzvik:matrix.org
For example, Riemann Curvature tensor of a 2d space would have shape (2,2,2,2). That means each point in space has a (2,2) tensor associated with it
This was a wrong explanation, BTW
12:35:30@ritzvik:matrix.orgRitwik SahaBut I stick to the point that Riemann Tensor is a fourth order tensor
12:35:37@ritzvik:matrix.orgRitwik Sahawith shape (a,a,a,a)
12:37:29@ritzvik:matrix.orgRitwik Saha greenturtle: The line you linked belonged to WeylTensor which is defined to be of order 2. So that shape for a dimension-3 space would be (3,3)
12:38:15@krisastern:matrix.orgK.S. Out of curiosity, greenturtle which GR textbook are you basing your arguments on?
12:41:57@ritzvik:matrix.orgRitwik SahaA very similar analogy would be Rotation matrix for 2D space has shape (2,2)
12:42:08@ritzvik:matrix.orgRitwik SahaLikewise for n-D space is (n,n)
12:42:20@ritzvik:matrix.orgRitwik SahaAnd not (n,n,n..... upto n times)
12:49:47@greenturtle:matrix.orggreenturtle Weyl Tensor is 4th order https://mathworld.wolfram.com/WeylTensor.html
12:50:00@greenturtle:matrix.orggreenturtle
In reply to @ritzvik:matrix.org
greenturtle: The line you linked belonged to WeylTensor which is defined to be of order 2. So that shape for a dimension-3 space would be (3,3)
* Weyl Tensor is 4th order https://mathworld.wolfram.com/WeylTensor.html
12:50:27@greenturtle:matrix.orggreenturtle
In reply to @ritzvik:matrix.org
And not (n,n,n..... upto n times)
This is exactly my point
12:50:52@greenturtle:matrix.orggreenturtle
In reply to @krisastern:matrix.org
Out of curiosity, greenturtle which GR textbook are you basing your arguments on?
I'm watching a video lecture series currently. I haven't used a particular book yet.
12:51:17@krisastern:matrix.orgK.S.I see
12:51:58@ritzvik:matrix.orgRitwik SahaIf that's the case then it should be (3,3,3,3)
12:52:18@greenturtle:matrix.orggreenturtleYup. the lectures by Frederick Schuller. Under the name of Winter school on gravity and light on youtube
12:52:51@ritzvik:matrix.orgRitwik SahaI'll open an issue if required, lemme see
12:54:22@greenturtle:matrix.orggreenturtlealso, since config is right there from the class Tensor. why don't we introduce a check to see the compatibility between config and the shape ? like we did with dimensions and shape
12:54:47@ritzvik:matrix.orgRitwik SahaYes, it's a fourth order one. I guess long time, no GR for me It's already defined as fourth order https://github.com/einsteinpy/einsteinpy/blob/272024339aa8ec2246d5e359bf53b0d981785871/src/einsteinpy/symbolic/weyl.py#L15
12:55:01@ritzvik:matrix.orgRitwik Sahaonly the part below the if statement is wrong
12:55:23@greenturtle:matrix.orggreenturtlethat's right
12:55:57@ritzvik:matrix.orgRitwik Saha
In reply to @greenturtle:matrix.org
that's right
Open an issue then? If that's okay with you
12:56:07@greenturtle:matrix.orggreenturtlesure !
12:56:33@greenturtle:matrix.orggreenturtle
In reply to @greenturtle:matrix.org
also, since config is right there from the class Tensor. why don't we introduce a check to see the compatibility between config and the shape ? like we did with dimensions and shape
while we're at it, I would recommend to implement this too
12:56:41@greenturtle:matrix.orggreenturtlewhat do you think
12:58:16@ritzvik:matrix.orgRitwik Saha
In reply to @greenturtle:matrix.org
while we're at it, I would recommend to implement this too
Yes, it’s already an issue #484
12:58:17@_neb_github:matrix.orgGithubhttps://github.com/einsteinpy/einsteinpy/issues/484 : Error handling for `config` variable in Tensor class
13:00:13@greenturtle:matrix.orggreenturtleawesome !

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