On Monday, March 3, 2014 11:30:50 AM UTC+1, Jeroen Demeyer wrote: > > > I have no clue what that error message means, and more importantly, how > to avoid it. > The concrete problem (I guess) is that 123633238138850861 is not a prime > number. But now the question becomes: where does this number come from? >
I must confess that I also don't see why a computation involving algebraic numbers should involve operations over some finite field. But since I know only little about the implementation details of algebraic numbers, I'll accept any statement that there is a good reason for doing this. Nevertheless, knowing that reason might help figuring out what goes wrong here. > > I've pasted my code from my norebook worksheet to > https://gist.github.com/gagern/9320350. > Can you please reduce the example code you posted? If you think this is > a bug in Sage, try to post the minimal amount of code that will > reproduce the bug. > I realize that reproducing this beast is pretty difficult: the first time I encounter one of these errors, it's this pari error about FpX_ffintersect, but if I execute exactly the same command a second time, I get the AttributeError for PolynomialTracker instead: AttributeError: 'AlgebraicPolynomialTracker' object has no attribute '_gen' This makes debugging the beast a lot harder, since I have to redo many computations for every step. Nevertheless, here is a minimal example: https://gist.githubusercontent.com/gagern/9320350/raw/d1896f7a5a05b24075098941c9c3ff156ca6c139/MinimalReprodcing6.sage It is minimal in the following sense: For the whole expression, the minpoly call fails with the claimed error message. For each operand, however, it succeeds. If I recreate each operand from its minimal polynomial, the call succeeds as well. So it must be not only the value stored in the first operand, but also the way it is encoded, represented, references other things and so on. The whole thing is far from minimal in terms of code length, but as I said, I can't make the expression any easier and still reproduce the issue. In terms of number of commands, it should be fairly close to minimal, but the command defining the expression is huge. On Monday, March 3, 2014 11:36:03 AM UTC+1, Jeroen Demeyer wrote:On 2014-03-03 09:11, [email protected] wrote: > I think as a general rule, you should try to avoid symbolic computations > for any serious work. Try to convert your problem to use a polynomial ring > instead. > I have to take square roots and even cubic roots along the way, which I can't do in a polynomial ring. At least not easily, not without defining a new field every time I need another square root. Or is there a simple way? -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
