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|    sci.math.symbolic    |    Symbolic algebra discussion    |    10,432 messages    |
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|    Message 10,264 of 10,432    |
|    Nasser M. Abbasi to Jeff Barnett    |
|    Re: Symbolic-Numeric Integration    |
|    04 Sep 22 00:24:23    |
      From: nma@12000.org              On 9/3/2022 11:25 PM, Jeff Barnett wrote:              Hello again:              > I would either       > give the system a fail because it is unreliable on that problem              Sorry, I do not understand the above. Suppose it returns some       antiderivative on one call. How is the program supposed to be it       failed or not?              The program has no verification on the anti-derivative that it satisfies       the integral. It just checkes the result and looks to see if the number of       terms that were not integrated is zero or not to decide if it was       able to integrate it fully or not.              > or I       > would test it for, say, a 100 or so seeds and give the number (a       > percent) that it gets correct.                     So you are saying to run the same integral 100 times, each with different seed       (say 1,2,3,4....,100 ?) saving all the results, then do histogram and       pick the anti-derivative that shows up the most frequent?              And if they are all different, what to do? Say it failed or pick one by random?              Sure, I could do that, but the time this will take will be prohibitive.              I have 12,500 integrals (picked out of 85,500 integrals, since Julia can       only do univariate ones with constant coefficients).              Lets say each call to integrate takes 25 seconds on average (I do       not have the average for Julia yet as the tests are still running, it       could be more or it could be much more) but looking at the terminal       now, some are more and some less. So have to wait to find       out what the average is.              Using 25 seconds per on call, this will result in 31,250,000 seconds or       about one year to finish just the Julia test. So it is not practical       for me to do such a setup. Doing parallel processing is beyond what       I can do on my PC.              So I think using one seed, as long as it is documented what it is, and       the result is reproducible can be considered as a compromise.              This is until Julia obtains an standard symbolic integrator. I read       somewhere that they are working on doing that for the future.              The fact that you had to search for a       > seed that led to correct behavior voids the system's ability for that       > example. It might be that you could find a seed for each problem in the       > test suite that leads to correct behavior for the problem. But that       > doesn't make the system perfect.       >       > Basically when you are testing a system that uses a "probabilistic"       > approach, you need to develop scoring methods that account for that fact.              --Nasser              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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