using Nemo
R, () = polynomial_ring(QQ, Symbol[])
x = one(R)
evaluate(x, [])
gives the following error:
ERROR: BoundsError: attempt to access 0-element Vector{QQMPolyRingElem} at index [1]
Stacktrace:
[1] throw_boundserror(A::Vector{QQMPolyRingElem}, I::Tuple{Int64})
@ Base ./essentials.jl:15
[2] getindex
@ ./essentials.jl:919 [inlined]
[3] evaluate(a::QQMPolyRingElem, bs::Vector{QQMPolyRingElem})
@ Nemo ~/.julia/packages/Nemo/kdloy/src/flint/fmpq_mpoly.jl:600
[4] evaluate(a::QQMPolyRingElem, vals::Vector{Any})
@ AbstractAlgebra ~/.julia/packages/AbstractAlgebra/T6WZD/src/MPoly.jl:862
[5] top-level scope
@ REPL[5]:1while evaluate(x, QQFieldElem[]) gives the desired result.
Indeed, in the functions below, S = parent(bs[1]) fails when bs is empty...
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function evaluate(a::QQMPolyRingElem, bs::Vector{QQMPolyRingElem}) |
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allequal(map(parent, bs)) || error("parents do not match") |
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R = parent(a) |
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S = parent(bs[1]) |
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|
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length(bs) != nvars(R) && |
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error("Number of variables does not match number of values") |
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|
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c = S() |
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fl = @ccall libflint.fmpq_mpoly_compose_fmpq_mpoly(c::Ref{QQMPolyRingElem}, a::Ref{QQMPolyRingElem}, bs::Ptr{Ref{QQMPolyRingElem}}, R::Ref{QQMPolyRing}, S::Ref{QQMPolyRing})::Cint |
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fl == 0 && error("Something wrong in evaluation.") |
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return c |
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end |
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|
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function evaluate(a::QQMPolyRingElem, bs::Vector{QQPolyRingElem}) |
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allequal(map(parent, bs)) || error("parents do not match") |
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R = parent(a) |
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S = parent(bs[1]) |
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|
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length(bs) != nvars(R) && |
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error("Number of variables does not match number of values") |
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|
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c = S() |
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fl = @ccall libflint.fmpq_mpoly_compose_fmpq_poly(c::Ref{QQPolyRingElem}, a::Ref{QQMPolyRingElem}, bs::Ptr{Ref{QQPolyRingElem}}, R::Ref{QQMPolyRing})::Cint |
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fl == 0 && error("Something wrong in evaluation.") |
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return c |
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end |
gives the following error:
ERROR: BoundsError: attempt to access 0-element Vector{QQMPolyRingElem} at index [1] Stacktrace: [1] throw_boundserror(A::Vector{QQMPolyRingElem}, I::Tuple{Int64}) @ Base ./essentials.jl:15 [2] getindex @ ./essentials.jl:919 [inlined] [3] evaluate(a::QQMPolyRingElem, bs::Vector{QQMPolyRingElem}) @ Nemo ~/.julia/packages/Nemo/kdloy/src/flint/fmpq_mpoly.jl:600 [4] evaluate(a::QQMPolyRingElem, vals::Vector{Any}) @ AbstractAlgebra ~/.julia/packages/AbstractAlgebra/T6WZD/src/MPoly.jl:862 [5] top-level scope @ REPL[5]:1while
evaluate(x, QQFieldElem[])gives the desired result.Indeed, in the functions below,
S = parent(bs[1])fails whenbsis empty...Nemo.jl/src/flint/fmpq_mpoly.jl
Lines 598 to 624 in f9ccb66