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  • Jun 17 20:24
    shreyasbapat commented #592
  • Jun 17 20:24
    shreyasbapat commented #592
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    shreyasbapat reopened #592
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  • May 19 18:47
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    shreyasbapat commented #588
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    shreyasbapat commented #588
Github
@_neb_github:matrix.org
[m]
einsteinpy/einsteinpy#573 : Update riemann.py
ozzyw
@ozzyw:matrix.org
[m]
thanks for your help!
ozzyw
@ozzyw:matrix.org
[m]

Hey there, I am working on a research project using einsteinpy. There were a lot of invariants that I needed that were not supported by einsteinpy.symbolic. so so far I've added 4 ricci invariants and 2 Weyl invariants. I will likely be adding all the Zakhary Mcintosh scalars as I go. I've also created a separate BaseRelativityScalar class similar to the Tensor one. Are these within the intended scope of that module? If so I'd like to make a pull request once I've done more testing.

I feel like this would be useful functionality for other metric analysis projects.

1 reply
amar123
@amar123:matrix.org
[m]
cannot import name 'four_position' from 'einsteinpy.coordinates.utils' (C:\Users\Lenovo\Anaconda3\lib\site-packages\einsteinpy\coordinates\utils.py) I found this error on import and i checked out the utils.py there is no any function name four_position on the utils.py file . but there is example given with this import
Amar Raj Ghimire
@amarghimire
from einsteinpy.coordinates.utils import four_position, stacked_vec I have checked the utils.py file but it doesnt contain any class / function named four_postion but I couldnt import "four_position" as on the suggested demo code of schwarzschild metric on einsteinpy doc .
Rei 머호
@rei_wu:matrix.org
[m]

techprog:matrix.org

Amar Raj Ghimire
@amarghimire

ImportError Traceback (most recent call last)

<ipython-input-2-f52a1194b34a> in <module>
1 import numpy as np
2
----> 3 from einsteinpy.coordinates.utils import four_position, stacked_vec
4 from einsteinpy.geodesic import Geodesic
5 from einsteinpy.metric import Schwarzschild

ImportError: cannot import name 'four_position' from 'einsteinpy.coordinates.utils' (C:\Users\Lenovo\Anaconda3\lib\site-packages\einsteinpy\coordinates\utils.py)

1 reply
rachitt_shah
@rachitt_shah:matrix.org
[m]
Are you using a virtual environment with all requirements installed?
Amar Raj Ghimire
@amarghimire
@rachitt_shah:matrix.org yes but my problem is utils.py doesnot contain any four_position , May be developers have changed the library but the demo code is not working.
amar123
@amar123:matrix.org
[m]
1 reply
JeS24
@jes0:matrix.org
[m]
On "stable" (v0.3.1 from PyPi), the Geodesic module requires a julia installation, since the solver is written in Julia and the Python interface is a wrapper over it. This has been tackled in the "latest" code (v0.4.dev0 on GitHub), that removes the Julia dependency but trades Julia's speed for Python's convenience. We are planning to develop the Julia code separately and perhaps have a backend switch, once the codebase matures.
Alberto Di Stazio
@tktk2746:matrix.org
[m]
hello, I am a beginner. I am trying some of the examples with good success, however I am struggling to import the Timelike / Nulllike geodesic. I get the following error : ImportError: cannot import name 'Timelike' from 'einsteinpy.geodesic' . I can import Geodesic module, but the Timelike/Nulllike does not work. What could be the issue? Any idea?
1 reply
shreyasbapat
@shreyasbapat:matrix.org
[m]
Banned
shreyasbapat
@shreyasbapat:matrix.org
[m]
This all is because of that one mess up that happened in the last release
April will see a new release which should fix all this
1 reply
Erik
@16dimensionalmathematician:matrix.org
[m]

Hi! I may have found a found a bug in einsteinpy. Either that or I have a fundamental misunderstanding about how to use it. The Riemann curvature tensor should always be skew symmetric: R_abcd = -R_abdc. However in the following example this is not the case. I am working with a 2D metric with line element ds^2 = -2 du dr - K(u, r) du^2:

import sympy
from einsteinpy.symbolic import MetricTensor, RiemannCurvatureTensor

syms= sympy.symbols("u r")
u, r = syms
K = sympy.Function("K")(u, r)
metric_array = [[-K, -1], [-1, 0]]
metric = MetricTensor(metric_array, syms)

rie = RiemannCurvatureTensor.from_metric(metric)
rie = rie.change_config("llll")
rie[0][1][1][0] == -rie[0][1][0][1] # Returns False

The last line should return true for any valid Riemann tensor if I understand correctly, but the R_urru component gives zero. Have I made a mistake or is this a bug? Am I accessing the tensor components incorrectly perhaps?

john-einsteinpy
@john-einsteinpy:matrix.org
[m]
Hey, did anyone who uses jupyter notebook(conda) manage to properly install einsteinpy on M1 mac?
I seem to run into problems like "cannot import name 'Timelike' from 'einsteinpy.geodesic'. ".
3 replies
john-einsteinpy
@john-einsteinpy:matrix.org
[m]
shreyasbapat said above that such problems are because of the last update broke things and that the next update in april ought to fix it.
1 reply
limedgestpen1970
@limedgestpen1970:matrix.org
[m]
Pal Szabo
@zabop
Hi everyone! I am also facing issues with four_position not being in einsteinpy.coordinates.utils. I understand that recently things broke recently; is there a version of einsteinpy which lets me visualize geodesics and currently works? :)
@limedgestpen1970:matrix.org I am pretty sure this is scam
JeS24
@jes0:matrix.org
[m]
@zabopThe latest version from GitHub should help: pip install git+https://github.com/einsteinpy/einsteinpy.git.
Pal Szabo
@zabop
Ohh maybe I am doing something wrong then. I am using this guide: https://docs.einsteinpy.org/en/stable/user_guide.html
and the result of my attempt is:
image.png
maybe the guide I am following is not the one I am supposed to be using with the latest einsteinpy version? :)
jes0
@jes0:matrix.org
[m]
Sorry, I should have explained. "stable" in this link (https://docs.einsteinpy.org/en/stable/user_guide.html) refers to the EinsteinPy version, you'd install using pip install einsteinpy. This would install einsteinpy-0.3.1 (AKA "stable"). What you want is einsteinpy-0.4.dev0 (AKA "latest"), that you can install via pip install git+https://github.com/einsteinpy/einsteinpy.git. This pulls the most recent code from our GitHub repo. The documentation for this version can be found at https://docs.einsteinpy.org/en/latest .
2 replies
I also recommend uninstalling the previous version using pip uninstall einsteinpy before you install the latest version.
@zabop
jezza1251
@jezza1251:matrix.org
[m]
Hi everyone! Currently using the latest version of einsteinpy (0.4dev0), and I'm trying to do this project - https://docs.einsteinpy.org/en/latest/examples/Using%20Geodesics%20%28Back-ends%20%26%20Plotting%29.html, however my plot seems very wrong compared to what's expected! Attached is my code and the plot, if anyone could help that'll be so great!
shreyasbapat
@shreyasbapat:matrix.org
[m]
Okay, finally I am back
The release should happen this weekend
And all these issues will get sprtef
Sorted*
smondal
@smondal:matrix.org
[m]
Hello guys, I have a naive question. It is fine to write the metric as for desitter or schwarzschild. I want to write a metric where the metric components are diag(F(t,r),G(t,r),E(t,r),D(t,r)). Where F,G,D,E are arbitrary function and not sin, cos or any other predefined function. How do I write that. Please help....
shreyasbapat
@shreyasbapat:matrix.org
[m]
EinsteinPy 0.4.0 is out 😁
1 reply
I am really sorry for not staying up to date here
This covid wave has hurt all of us here pretty badly
2 replies
Sourodip Ghoshdastidar
@geekyboy:matrix.org
[m]
how can i use the cartesian to spherical coordinates conversion module?
1 reply
i am new to python sorry
rh99
@rh99:matrix.org
[m]
Hi, can I contribute to this project without knowledge of general relativity? I will be taking a class on it next year...
1 reply
Thomas Andersen
@tomandersen:matrix.org
[m]
m1 Mac install - I have tried quite a bit, and pip methods all fail, usually on llvmlite. When I use conda it 'works' but in Jupyter I can't import or use it. Also trying to use it in python3 in a small python file or interactive fails, it can't see the installed by conda version. All the other python modules i need install. It's installing or trying to using native arm64 code. Thanks for any tips! Was trying out EinsteinPy and it was great getting the Einstein tensor from a metric. I tried on a different computer from mine.
shreyasbapat
@shreyasbapat:matrix.org
[m]
Yeah. I don't know what to do about it. I am sorry for that. Will have to get a M1 to try it out.
I am sure it is because either Numba does not support M1
Thomas Andersen
@tomandersen:matrix.org
[m]
I figured it out. Install everything with conda. (which all worked for me). Then only problem is macs use zsh shell, needed to cd into the conda bin directory and type ./conda init zsh

tandersen@tomm1 bin % ./conda init zsh
no change /opt/homebrew/Caskroom/miniforge/base/condabin/conda
no change /opt/homebrew/Caskroom/miniforge/base/bin/conda
no change /opt/homebrew/Caskroom/miniforge/base/bin/conda-env
no change /opt/homebrew/Caskroom/miniforge/base/bin/activate
no change /opt/homebrew/Caskroom/miniforge/base/bin/deactivate
no change /opt/homebrew/Caskroom/miniforge/base/etc/profile.d/conda.sh
no change /opt/homebrew/Caskroom/miniforge/base/etc/fish/conf.d/conda.fish
no change /opt/homebrew/Caskroom/miniforge/base/shell/condabin/Conda.psm1
no change /opt/homebrew/Caskroom/miniforge/base/shell/condabin/conda-hook.ps1
no change /opt/homebrew/Caskroom/miniforge/base/lib/python3.9/site-packages/xontrib/conda.xsh
no change /opt/homebrew/Caskroom/miniforge/base/etc/profile.d/conda.csh
modified /Users/tandersen/.zshrc

==> For changes to take effect, close and re-open your current shell. <==

tandersen@tomm1 bin % pwd
/opt/homebrew/Caskroom/miniforge/base/bin

Then it worked. I needed to get conda to set up my zsh shell so typing jupyter-lab would run the correct one.