Can't expand identically zero functions with `Legendre()`

[DanielVandH]

using ClassicalOrthogonalPolynomials
P = Legendre()
julia> P \ (Returns(0.0).(axes(P, 1)))
ERROR: ArgumentError: invalid GenericMemory size: too large for system address width
Stacktrace:
  [1] GenericMemory
    @ .\boot.jl:515 [inlined]
  [2] Array
    @ .\boot.jl:580 [inlined]
  [3] Array
    @ .\boot.jl:593 [inlined]
  [4] zeros
    @ .\array.jl:578 [inlined]
  [5] zeros
    @ .\array.jl:574 [inlined]
  [6] _cheb2legTH_TLC(::Type{Float64}, mn::Tuple{Int64}, d::Int64)
    @ FastTransforms C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:218
  [7] _broadcast_getindex_evalf
    @ .\broadcast.jl:673 [inlined]
  [8] _broadcast_getindex
    @ .\broadcast.jl:656 [inlined]
  [9] #17
    @ .\broadcast.jl:1097 [inlined]
 [10] ntuple
    @ .\ntuple.jl:48 [inlined]
 [11] copy
    @ .\broadcast.jl:1097 [inlined]
 [12] materialize
    @ .\broadcast.jl:867 [inlined]
 [13] plan_th_cheb2leg!(::Type{Float64}, mn::Tuple{Int64}, dims::Tuple{Int64})
    @ FastTransforms C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:235
 [14] plan_th_cheb2leg!
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:651 [inlined]
 [15] th_cheb2leg
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:652 [inlined]
 [16] transform_ldiv
    @ C:\Users\danjv\.julia\packages\ClassicalOrthogonalPolynomials\3YYrU\src\classical\legendre.jl:98 [inlined]
 [17] basis_ldiv_size
    @ C:\Users\danjv\.julia\packages\ContinuumArrays\uaOZ9\src\bases\bases.jl:332 [inlined]
 [18] copy
    @ C:\Users\danjv\.julia\packages\ContinuumArrays\uaOZ9\src\bases\bases.jl:324 [inlined]
 [19] materialize
    @ C:\Users\danjv\.julia\packages\ArrayLayouts\31idh\src\ldiv.jl:22 [inlined]
 [20] ldiv
    @ C:\Users\danjv\.julia\packages\ArrayLayouts\31idh\src\ldiv.jl:98 [inlined]
 [21] \(A::Legendre{Float64}, B::QuasiArrays.BroadcastQuasiVector{Float64, Returns{Float64}, Tuple{Inclusion{…}}})
    @ QuasiArrays C:\Users\danjv\.julia\packages\QuasiArrays\nTH6k\src\matmul.jl:34
 [22] top-level scope
    @ REPL[34]:1
Some type information was truncated. Use `show(err)` to see complete types.

This is on v1.11, but the error is similar for v1.10

julia> P \ (Returns(0.0).(axes(P, 1)))
ERROR: ArgumentError: invalid Array dimensions
Stacktrace:
  [1] Array
    @ .\boot.jl:477 [inlined]
  [2] Array
    @ .\boot.jl:486 [inlined]
  [3] zeros
    @ .\array.jl:636 [inlined]
  [4] zeros
    @ .\array.jl:632 [inlined]
  [5] _cheb2legTH_TLC(::Type{Float64}, mn::Tuple{Int64}, d::Int64)
    @ FastTransforms C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:218
  [6] _broadcast_getindex_evalf
    @ .\broadcast.jl:709 [inlined]
  [7] _broadcast_getindex
    @ .\broadcast.jl:692 [inlined]
  [8] #31
    @ .\broadcast.jl:1118 [inlined]
  [9] ntuple
    @ .\ntuple.jl:48 [inlined]
 [10] copy
    @ .\broadcast.jl:1118 [inlined]
 [11] materialize
    @ .\broadcast.jl:903 [inlined]
 [12] plan_th_cheb2leg!
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:235 [inlined]
 [13] plan_th_cheb2leg!
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:651 [inlined]
 [14] th_cheb2leg
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:652 [inlined]
 [15] transform_ldiv(::Legendre{Float64}, f::QuasiArrays.BroadcastQuasiVector{Float64, Returns{Float64}, Tuple{Inclusion{…}}})
    @ ClassicalOrthogonalPolynomials C:\Users\danjv\.julia\packages\ClassicalOrthogonalPolynomials\3YYrU\src\classical\legendre.jl:98
 [16] basis_ldiv_size
    @ C:\Users\danjv\.julia\packages\ContinuumArrays\uaOZ9\src\bases\bases.jl:332 [inlined]
 [17] copy
    @ C:\Users\danjv\.julia\packages\ContinuumArrays\uaOZ9\src\bases\bases.jl:324 [inlined]
 [18] materialize
    @ C:\Users\danjv\.julia\packages\ArrayLayouts\31idh\src\ldiv.jl:22 [inlined]
 [19] ldiv
    @ C:\Users\danjv\.julia\packages\ArrayLayouts\31idh\src\ldiv.jl:98 [inlined]
 [20] \(A::Legendre{Float64}, B::QuasiArrays.BroadcastQuasiVector{Float64, Returns{Float64}, Tuple{Inclusion{…}}})
    @ QuasiArrays C:\Users\danjv\.julia\packages\QuasiArrays\nTH6k\src\matmul.jl:34
 [21] top-level scope
    @ REPL[5]:1
Some type information was truncated. Use `show(err)` to see complete types.

[dlfivefifty]

This might be a bug in FastTransforms.jl that it can't handle empty vectors, though perhaps I work around it for Chebyshev...

[DanielVandH]

Indeed:

julia> e = Float64[];

julia> FastTransforms.th_cheb2leg(e)
ERROR: ArgumentError: invalid Array dimensions
Stacktrace:
  [1] Array
    @ .\boot.jl:477 [inlined]
  [2] Array
    @ .\boot.jl:486 [inlined]
  [3] zeros
    @ .\array.jl:636 [inlined]
  [4] zeros
    @ .\array.jl:632 [inlined]
  [5] _cheb2legTH_TLC(::Type{Float64}, mn::Tuple{Int64}, d::Int64)
    @ FastTransforms C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:218
  [6] _broadcast_getindex_evalf
    @ .\broadcast.jl:709 [inlined]
  [7] _broadcast_getindex
    @ .\broadcast.jl:692 [inlined]
  [8] #31
    @ .\broadcast.jl:1118 [inlined]
  [9] ntuple
    @ .\ntuple.jl:48 [inlined]
 [10] copy
    @ .\broadcast.jl:1118 [inlined]
 [11] materialize
    @ .\broadcast.jl:903 [inlined]
 [12] plan_th_cheb2leg!
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:235 [inlined]
 [13] plan_th_cheb2leg!
    @ C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:651 [inlined]
 [14] th_cheb2leg(::Vector{Float64})
    @ FastTransforms C:\Users\danjv\.julia\packages\FastTransforms\S7huq\src\toeplitzhankel.jl:652
 [15] top-level scope
    @ REPL[14]:1

Not all the th_ functions have an issue like this, e.g.

julia> FastTransforms.th_ultra2ultra(e, 0.0, 1.0)
Float64[]

is fine. I'll make an issue on FastTransforms.jl.

[DanielVandH]

Will close since it's not an issue in this repo