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Re: how long is a long evaluation?
psalzman at landau.ucdavis.edu wrote in message <7q2158$q9s at smc.vnet.net>... >dear all, > >i have a triple integral of a gaussian and a bunch of step functions of 4 >variables. the expression is not that difficult, but it's not exactly 2+2 >either. > >last night i started Mathematica on it. went to bed 4 hours later and when i looked >in the morning, it had reported "out of memory" (i have 96MB). > >next i tried doing the integral with only one of the step functions to see >if that sped things up. so far it's been 4 hours and Mathematica is still plugging >away. > >i'm beginning to suspect that the way i've entered the integral is wrong. >i asked the department "mathematica guru" but he had no words of wisdom for >me. > >1- is there a way of telling if Mathematica is still plugging away or is just hung >in some kind infinite loop? can i see what Mathematica is working on at any given >moment? what is a reasonable maximum time for a difficult symbolic triple >integral? has anyone had something like this that ran for more than 4 >hours? (dual PII/266) > >2- would someone be kind enough to look at this notebook? it's 4 cells >long (so it's terribly short) and i'm sure if there's a mistake, it will be >glaring to the trained eye. > >my *sincerest* thanks to anyone who can help. > >pete > Unfortunately there will always be computer algebra problems that generate a combinatorial explosion when you try to run them. Yours may be of that type, or there may be something that can be corrected. I do not know if you sent your notebook as an attachment, but it is not here with your message. I suggest you post again with the text of your notebook appended to the message. You can remove all the stuff before Notebook[ and all the stuff at the end about cache information. David Bailey Salford Software