| 10 Apr 2020 |
| 12:32:21 |  greenturtle | * The Weyl tensor should have four 'slots' in its shape. Always. what goes in each slot is the number of dimensions |
| 12:33:34 |  Ritwik Saha | Lemme see |
| 12:34:18 | greenturtle | please |
| 12:35:10 | Ritwik 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 | Ritwik Saha | But I stick to the point that Riemann Tensor is a fourth order tensor |
| 12:35:37 | Ritwik Saha | with shape (a,a,a,a) |
| 12:37:29 | Ritwik 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 |  K.S. | Out of curiosity, greenturtle which GR textbook are you basing your arguments on? |
| 12:41:57 | Ritwik Saha | A very similar analogy would be Rotation matrix for 2D space has shape (2,2) |
| 12:42:08 | Ritwik Saha | Likewise for n-D space is (n,n) |
| 12:42:20 | Ritwik Saha | And not (n,n,n..... upto n times) |
| 12:49:47 | greenturtle | Weyl Tensor is 4th order https://mathworld.wolfram.com/WeylTensor.html |
| 12:50:00 | greenturtle | 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 | In reply to @ritzvik:matrix.org
And not (n,n,n..... upto n times) This is exactly my point |
| 12:50:52 | greenturtle | 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 | K.S. | I see |
| 12:51:58 | Ritwik Saha | If that's the case then it should be (3,3,3,3) |
| 12:52:18 | greenturtle | Yup. the lectures by Frederick Schuller. Under the name of Winter school on gravity and light on youtube |
| 12:52:51 | Ritwik Saha | I'll open an issue if required, lemme see |
| 12:54:22 | greenturtle | 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 |
| 12:54:47 | Ritwik Saha | Yes, 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 | Ritwik Saha | only the part below the if statement is wrong |
| 12:55:23 | greenturtle | that's right |
| 12:55:57 | Ritwik Saha | In reply to @greenturtle:matrix.org
that's right Open an issue then? If that's okay with you |
| 12:56:07 | greenturtle | sure ! |
| 12:56:33 | greenturtle | 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 | what do you think |
| 12:58:16 | Ritwik 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 |  Github | https://github.com/einsteinpy/einsteinpy/issues/484 : Error handling for `config` variable in Tensor class |
| 13:00:13 | greenturtle | awesome ! |
