Segmentation fault when calling Tate's algorithm

[simonbrandhorst]

julia> using Hecke
 _    _           _        
| |  | |         | |         |  Software package for
| |__| | ___  ___| | _____   |  algorithmic algebraic number theory
|  __  |/ _ \/ __| |/ / _ \  |  
| |  | |  __/ (__|   <  __/  |  Manual: https://thofma.github.io/Hecke.jl
|_|  |_|\___|\___|_|\_\___|  |  Version 0.34.8-dev

julia> K,s = rational_function_field(GF(2),:s)
(Rational function field over GF(2), s)

julia> E = elliptic_curve(K,[0,1,s,1,1])
Elliptic curve with equation
y^2 + s*y = x^3 + x^2 + x + 1

julia> tates_algorithm_local(E,K(0))

[6337] signal (11.1): Segmentation fault
in expression starting at REPL[4]:1
fmpz_invmod at /workspace/srcdir/flint/src/fmpz/invmod.c:36
fq_ctx_init_modulus at /workspace/srcdir/flint/src/fq/ctx_init_modulus.c:38
gr_ctx_init_fq_modulus_fmpz_mod_poly at /workspace/srcdir/flint/src/gr/fq.c:771
gr_ctx_init_fq_modulus_nmod_poly at /workspace/srcdir/flint/src/gr/fq.c:786
fq_default_ctx_init_modulus_nmod_type at /workspace/srcdir/flint/src/fq_default/ctx.c:160
_fq_field_from_nmod_poly_in_disguise at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:579
#527 at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:609
get_cached! at /home/simonbrandhorst/.julia/packages/AbstractAlgebra/AqzuZ/src/AbstractAlgebra.jl:159 [inlined]
FqField at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:602 [inlined]
#_residue_field#543 at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:736 [inlined]
_residue_field at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:732 [inlined]
_residue_field at /home/simonbrandhorst/.julia/packages/Nemo/Mhf6i/src/flint/fq_default_extended.jl:732 [inlined]
residue_field at /home/simonbrandhorst/.julia/dev/Hecke/src/GenOrd/Ideal.jl:584 [inlined]
_tates_algorithm at /home/simonbrandhorst/.julia/dev/Hecke/src/EllCrv/LocalData.jl:63
_tates_algorithm at /home/simonbrandhorst/.julia/dev/Hecke/src/EllCrv/LocalData.jl:79
tates_algorithm_local at /home/simonbrandhorst/.julia/dev/Hecke/src/EllCrv/LocalData.jl:24
unknown function (ip: 0x7fbd64f7c68b)
_jl_invoke at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
do_call at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/interpreter.c:126
eval_value at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/interpreter.c:223
eval_stmt_value at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/interpreter.c:174 [inlined]
eval_body at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/interpreter.c:617
jl_interpret_toplevel_thunk at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/interpreter.c:775
jl_toplevel_eval_flex at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/toplevel.c:934
jl_toplevel_eval_flex at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/toplevel.c:877
ijl_toplevel_eval_in at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/toplevel.c:985
eval at ./boot.jl:385 [inlined]
eval_user_input at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:150
repl_backend_loop at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:246
#start_repl_backend#46 at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:231
start_repl_backend at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:228
_jl_invoke at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:3076
#run_repl#59 at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:389
run_repl at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/REPL/src/REPL.jl:375
jfptr_run_repl_91745.1 at /home/simonbrandhorst/julia-1.10.2/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:3076
#1013 at ./client.jl:432
jfptr_YY.1013_82712.1 at /home/simonbrandhorst/julia-1.10.2/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
jl_f__call_latest at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/builtins.c:812
#invokelatest#2 at ./essentials.jl:892 [inlined]
invokelatest at ./essentials.jl:889 [inlined]
run_main_repl at ./client.jl:416
exec_options at ./client.jl:333
_start at ./client.jl:552
jfptr__start_82738.1 at /home/simonbrandhorst/julia-1.10.2/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
true_main at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/jlapi.c:582
jl_repl_entrypoint at /cache/build/builder-amdci5-1/julialang/julia-release-1-dot-10/src/jlapi.c:731
main at julia (unknown line)
__libc_start_call_main at /lib64/libc.so.6 (unknown line)
__libc_start_main at /lib64/libc.so.6 (unknown line)
unknown function (ip: 0x4010b8)
Allocations: 4612450 (Pool: 4609141; Big: 3309); GC: 6
Segmentation fault (core dumped)

[simonbrandhorst]

Okay the input is nonsense, but it should not give a segfault.

[thofma]

Agreed, it should not segfault

[thofma]

julia> is_irreducible(numerator(K(0)))
true

:(