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Math Help - Length of time for Mathematica to finish "running"

  1. #1
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    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
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  2. #2
    A Plied Mathematician
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    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?
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  3. #3
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    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
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  4. #4
    A Plied Mathematician
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    Are you on a Windows Machine? Or Mac? Or Linux?
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  5. #5
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    I am using Windows
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  6. #6
    A Plied Mathematician
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    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?
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  7. #7
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    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
    Attached Thumbnails Attached Thumbnails Length of time for Mathematica to finish "running"-mathematica.jpg  
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  8. #8
    A Plied Mathematician
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    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.
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  9. #9
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    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...
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  10. #10
    A Plied Mathematician
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    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.
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  11. #11
    A Plied Mathematician
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    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.
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