Thread: Length of time for Mathematica to finish "running"

Hello all,

I am new to mathematica. I was just wondering in general how long it should take mathematica to solve something. I have a massive system of equations and it just says "running" forever. My question is, if it takes a long time (>45 minutes) can I safely say its stuck in a loop and cannot solve what I am asking (my computer is decent at the very least).

Thanks for your help!

Nick

Ha. Solving your system you posted about earlier? Well, I can tell you one thing: I've had algorithms run that reliably took two hours to complete. Any chance you could get a screenshot of your system of equations?

Hi Again,

Yes that is the one... spent ages typing it out just to see it not give me anything. I am not sure how to upload a screenshot to this thing unfortunately :/. I am going to leave it running overnight then I might try to harass you all again tomorrow when it will inevitably still be running. Cheers,

Nick

Are you on a Windows Machine? Or Mac? Or Linux?

I am using Windows

Ok, so do a "Print Screen". It'll be a key somewhere in the upper-right corner. You might need to hold down the shift key, or on a laptop, the function key. Then paste the clipboard into MS Paint or some program that's similar, and save it as a jpg. Then you can attach it to a post in this thread. You follow?

Here my stuff is... I can potentially delete a third of these equations and treat a third of my endogenous variables as exogenous if I want (although I still get the same running forever problem). Thanks a lot for your time,

Nick

Yeah, that's a horrendously nonlinear system. I don't think Mathematica is ever going to find a solution for you on that one. I would highly recommend a numerical method. You might be able to do a multi-dimensional Newton-Raphson technique.

I suspected as much, even if I eliminated half the equations do you think it will still be unable to do anything? Thanks a lot for your time by the way...

I think it would still have some severe issues. Incidentally, your phirj equation doesn't have a comma after it. You could try running it with the comma, but I suspect you'll still have difficulties.

You're very welcome for whatever help I can provide.

I should also point out that there are 20 equations, but 21 unknowns. Even theoretically, the best you can hope for is a 1-parameter family of solutions.