Recent content by Arman777

Fair enough :approve: Indeed that Is the case. However, the program is still in the development process. I can probably implement a custom function support but I am not sure I can add solving coupled PDE’s. Maybe I can… Feedback is very important for me and thanks for your sharing your...

Let me clarify this statement a bit more... The one important point in GTRPy is that the variables defined in the metric tensor **must be constant**. For example, you can write the Schwarzschild Coordinates System as g = diag[-(1-r_s/r), (1-r_s/r)**(-1), r^2, r^2sin^2(theta)] and that is...

That is also a great tool. However, I think GTRPy is better in some regards w.r.t einsteinpy 1) GTRPy is GUI based and more user-friendly than einsteinpy 2) GTRPy can also perform field operations

Yes indeed that is the case. The program sadly cannot perform that operation. The extra variables (variables other than the coordinate system) put in the metric is taken as constants and not as variables. This means that if you put any symbol other than the coordinate system, it will considered...

Hello, everyone I am now working on this project quite a while now and I just wanted to share it with this forum, which I was a member for a long time. I am working on a python application about GR and I believe I managed to create a very user-friendly layout. It's called GTRPy, and it allows...

https://github.com/seVenVo1d/grpy

I am trying to understand the series expansion of $$(1-cx)^{1/x}$$ The wolframalpha seems to solve the problem by using taylor series for ## x\rightarrow 0## and Puiseux series for ##x\rightarrow \infty##. Any ideas how can I calculate them ...

I have a 3 data column ##(X, Y, Z)## ranges from ##(min, max)##. For example, ##X = (0, 5)##, ##Y=(0, 3)##, ##Z=(0, 2)##. By using them I need to create a numpy array in the form of ##[(0, 0, 0), (0, 0, 1), (0, 0, 2), (0, 1, 0), (0, 1, 1), (0, 1, 2), (0, 2, 0)...]## So in total there will be...

Is there a book or article that discusses the scalar/tensor/scalar-tensor (maybe others as well) theories ? (Look at this wiki page for a general overview of the theories that I am talking about) So, I am looking for a book that discusses these theories either in general or in detail. It does...

Thanks for the help..

I am trying to move files and folders from one directory to other. Both of the files has multiple subfolders and files. From the reasearch I have made it seems that the answer should be something like, `cp mv -vr \Downloads\* .` But I am not sure this is true or not. I am also not sure about...

I am trying to understand this graph but I am confused about the distance definitions. So there's an object located at a comoving distance ##r##. The proper distance of the object at ##z'## can be written as $$d(z{'}) = \frac{1}{1+z{'}}\int_0^{z{'}} \frac{dz{'}}{H(z{'})}$$ In this case...

I am trying to find the comoving distance, $$\chi = c\int_0^z \frac{dz}{H(z)}$$ for the ##\Lambda##CDM model (spatially flat universe, containing only matter and ##\Lambda##). $$H^2 = H_0^2[\Omega_{m,0}(1+z)^3 + \Omega_{\Lambda, 0}]$$ When I put this into integral I am getting, $$\chi =...

I have learned at undergrad but know I have completely forget about it..

Let us suppose I have a value measured from experiment and given by $$V_{\text{exp}} \pm \sigma_{V_{\text{exp}}}$$ and a theoretical value given as $$V_{\text{the}} \pm \sigma_{V_{\text{the}}}$$ Is there a statistical way to measure how well ##V_{\text{the}}## matches with the...