fmpz_mpoly_pfrac_init: internal error about flint

[tthsqe12]

This one doesn't look too bad to fix. While I am installing 3.1.3, could you, @F-Feng, change the string in fmpz_mpoly_set_str_pretty to the more wieldy factored form you just displayed?
It is highly unlikely the set_str function has a bug.

[albinahlback]

That's a long polynomial! Can you print the exact error message you get? What version of FLINT are you using?

It shouldn't error inside fmpz_mpoly_pfrac_init. I suspect fmpz_mpoly_set_str_pretty is wrong in that case.

[F-Feng]

Apologies for the lengthy polynomial. I encountered this issue during my research, which is why I have included the entire polynomial here.

I am using flint-3.1.3, and the complete error message from the terminal appears as follows:

Flint exception (General error):
    fmpz_mpoly_pfrac_init: internal errorAborted (core dumped)

PS: The function fmpz_mpoly_set_str_pretty returns 0, indicating that fmpz_mpoly_set_str_pretty may work in this case.

[albinahlback]

Not sure if we will be able to solve this quickly. If you are able to answer these questions, it could be helpful in investigating this:

• Where does this polynomial arise?
• Do you know of any characteristics of this polynomial? (For instance, I think I see that it is not a homogeneous polynomial)
• Have you checked if fmpz_mpoly_set_str_pretty yields the correct output? (The initialization should always work, but just to make sure that this indeed is the problematic representation of this polynomial for fmpz_mpoly_pfrac_init)

[F-Feng]

Thank you for your response. Please take your time. I hope the following information may be helpful.

• The polynomial arises from my calculations of certain Feynman diagrams in Particle Physics, which often result in lengthy polynomials.
• I suspect that these polynomials do not exhibit any specific characteristics and are generally non-homogeneous.
• After using fmpz_mpoly_set_str_pretty, I verified the output with fmpz_mpoly_get_str_pretty and obtained the correct result.

[F-Feng]

By the way, here is the factorized output for the polynomial:

[F-Feng]

@tthsqe12 Thanks a lot, and here is the string in the factored form,

"-((-1+x3+x4)^2*(x3+x4)*(-x1+x1^2-x2+x1*x2+x2*x3+x2*x4)*(-(x1*x2*x3)+x1^2*x2*x3-x2^2*x3+x1*x2^2*x3-2*x2*x3^2+3*x1*x2*x3^2-x1^2*x2*x3^2+4*x2^2*x3^2-x1*x2^2*x3^2+2*x2*x3^3-2*x1*x2*x3^3-3*x2^2*x3^3+2*x1^2*x4-4*x1^3*x4+2*x1^4*x4+3*x1*x2*x4-7*x1^2*x2*x4+4*x1^3*x2*x4+x2^2*x4-3*x1*x2^2*x4+2*x1^2*x2^2*x4+x1*x3*x4-2*x1^2*x3*x4+x1^3*x3*x4-3*x2*x3*x4-x1*x2*x3*x4+4*x1^2*x2*x3*x4+3*x2^2*x3*x4+3*x1*x2^2*x3*x4+5*x2*x3^2*x4-5*x1*x2*x3^2*x4-6*x2^2*x3^2*x4+x1*x4^2-2*x1^2*x4^2+x1^3*x4^2-x2*x4^2-4*x1*x2*x4^2+5*x1^2*x2*x4^2-x2^2*x4^2+4*x1*x2^2*x4^2+4*x2*x3*x4^2-4*x1*x2*x3*x4^2-3*x2^2*x3*x4^2+x2*x4^3-x1*x2*x4^3)*x5^2)"