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##### Activity
• Jan 31 20:43

JeS24 on main

Updated README.rst to fix build… (compare)

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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
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.
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:
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 😁
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?
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...
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
modified /Users/tandersen/.zshrc

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

tandersen@tomm1 bin % pwd

Then it worked. I needed to get conda to set up my zsh shell so typing jupyter-lab would run the correct one.
@penuss:matrix.org
@pimmlel:matrix.org
[m]
Hi guys, I was reading through the docs to see if I could improve some things. One thing that I noticed is that you write "space-time" instead of "spacetime". Is this a stylistic choice of yours? Usually, it's written as "spacetime" in books and papers. The rationale behind that is that space and time are intrinsically linked. This isn't reflected when using a dash to separate both.
Disclaimer: I am coming more from a physics background rather than coding background.
Bernhard Umlauf
@bernie67:matrix.org
[m]
Hi all, first try to use einsteinpy. Can someone tell, how to declare user defined metrics? I want to use modified Schwarzschild metric, i.e. multiply g_rr with 1/r.
I get also an error message, if i use "from einsteinpy.symbolic import SchwarzschildMetric"
DottMichela Lai
@michelalai:matrix.org
[m]
Hi everyone! I am Michela, Post-Doc at University of Cagliari, Italy. I am just starting with einsteinpy. Thank you for what have you done so far, and hope I will be able to contribute to this project soon!
DottMichela Lai
@michelalai:matrix.org
[m]

Hi! Sorry for bothering for the very first day, but I noticed that the pip installing is complaining that
einsteinpy requires Python '>=3.7' but the running Python is 2.7.17

while I just installed python 3.8, and also the alias "python" points to that one, so why does it search for the oldest python? How can I force it to choose the 3.8 version I installed?

DottMichela Lai
@michelalai:matrix.org
[m]
Hi! hope This time will be easier

Processing /project/6004969/mlai92/einsteinpy
Installing collected packages: UNKNOWN
Running setup.py install for UNKNOWN ... error
Complete output from command /usr/bin/python2 -u -c "import setuptools, tokenize;file='/tmp/pip-Ycu7Ai-build/setup.py';exec(compile(getattr(tokenize, 'open', open)(file).read().replace('\r\n', '\n'), file, 'exec'))" install --record /tmp/pip-oH81vU-record/install-record.txt --single-version-externally-managed --compile:
/usr/lib64/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'setup_cfg'
warnings.warn(msg)
running install
running build
running install_egg_info
running egg_info
creating UNKNOWN.egg-info
writing UNKNOWN.egg-info/PKG-INFO
writing top-level names to UNKNOWN.egg-info/top_level.txt
writing manifest file 'UNKNOWN.egg-info/SOURCES.txt'

reading manifest file 'UNKNOWN.egg-info/SOURCES.txt'
warning: no files found matching '*.py' under directory 'src/einsteinpy/tests'
warning: no files found matching '*.html' under directory 'src/einsteinpy/tests'
no previously-included directories found matching 'docs/source/examples/.ipynb_checkpoints'
warning: no previously-included files matching '*.py[cod]' found anywhere in distribution
warning: no previously-included files matching '__pycache__' found anywhere in distribution
warning: no previously-included files matching '*.so' found anywhere in distribution
warning: no previously-included files matching '*.dylib' found anywhere in distribution
writing manifest file 'UNKNOWN.egg-info/SOURCES.txt'
Copying UNKNOWN.egg-info to /usr/lib/python2.7/site-packages/UNKNOWN-0.0.0-py2.7.egg-info
error: /usr/lib/python2.7/site-packages/UNKNOWN-0.0.0-py2.7.egg-info: Permission denied

----------------------------------------

Command "/usr/bin/python2 -u -c "import setuptools, tokenize;file='/tmp/pip-Ycu7Ai-build/setup.py';exec(compile(getattr(tokenize, 'open', open)(file).read().replace('\r\n', '\n'), file, 'exec'))" install --record /tmp/pip-oH81vU-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-Ycu7Ai-build/

This is the output when I try to install it from the git repository. The python version is 3.7.7
Any idea of how can I solve this?
DottMichela Lai
@michelalai:matrix.org
[m]
oky, I solved the issue. Let me know if anyone want to work together
Hi, I'm a bit confused by the indices of the Riemann tensors calculated by EinsteinPy. I have a 3D metric, so the Riemann tensor is a 3x3 matrix (I'll call it the outer matrix) where each element is another 3x3 matrix (the inner matrices). I assumed the indexing would be $R^{a}_{bcd}$ with a being the row of the outer matrix, b being columns, and then c&d being the respective indices for the inner matrices. This doesn't appear to be the case when I compare my Riemann tensor generated by EinsteinPy to hand calculations.