Recent content by cosmicstring1

Have you uninstalled any programs lately? If so, try reinstalling them. The uninstallation may remove some important files causing the blue screen. It may be nice to backup your important files anyway. An affordable portable hdd or a link cable to a desktop pc with a large hdd does the job...

See the help page for PlotLegend command.

Is the printer working fine for any other computer? If you are sure that the printer is faulty, try to change the cable between the printer and pc.

Scan your pc in safe mode with spybot and ad-aware, then your virus program. Do not forget to update them before going to the safe mode.

If you can use TeX or LateX to type your document, you may use the TeXForm[result] command in Mathematica to see the "result" in TeX form, then you can copy-paste it. By the way, there was a program (not free) which translates LaTeX files into Word files but I do not remember the name.

Everything has seemed all right because I have changed the eta in my metric file for the Euclidean sign and it gave the Weyl scalars and spin coeff.s right. The Ricci scalars' computation was the problem.

Yes, the mystery is solved. I have already checked my tetrad and it gives the metric right. I have changed the signature by hand and I did not use the nptetrad command (it really changes the signature which is not valid for my Euclidean case). I think my tetrad is not the right choice for...

I calculated Ricci scalar and Ricci tensor directly from grtensor and it also gives zero for the both.

Yes, I am referring to the great GRTensorII. I checked the tetrad from two articles and it satisfies the relations needed (I also checked by hand). I was thinking the Ricci scalar might be a combination of some NP Ricci scalars after having nonzero values. By the way, the both answers satisfy...

I calculate trace-free Ricci scalars (Phi00, Phi01,Phi02, etc) and scalar of curvature (Lambda=R/24) in Newman-Penrose formalism using a computer package. How can I find the Ricci scalar out of them? I though R was the Ricci scalar but Lambda comes non-zero for a spacetime whose Ricci scalar is...

I recommend Maple for a mathematician but before buying a software consult to your department's system administrator. Some universities have a campus license for some programs. Learning Maple may be harder than some other but it worths. I also recommend you to learn a programming language like...

Mathematica is the easiest with its palettes as an "advanced calculator". But if you want to expertise in mathematical or theoretical physics Maple worths studying. If you will be dealing with large matrices or more "engineering" stuff, Matlab must be your choice. In my opinion, Mathematica is...

Try "Part" command as Part[Solve[(t - a)*(t - 4) == 0, t], 2, 1, 2]

As a quick but not too usable solution, you can zip long named files and transfer these zip files.

Yes, I read that section from MTW but it does not give the answer. I do'nt have Flanders' book.