findblock for RealInfinity() (#190)

* findblock for realinfinity

* ci

Author: DanielVandH

.github/workflows/ci.yml

@@ -37,7 +37,8 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.10'
+          - '1'
+          - 'lts'
         os:
           - ubuntu-latest
           - macOS-latest

src/InfiniteLinearAlgebra.jl

@@ -34,7 +34,7 @@ import FillArrays: AbstractFill, AbstractFillMatrix, axes_print_matrix_row, geti
 
 import InfiniteArrays: AbstractInfUnitRange, InfAxes, InfRanges, InfStepRange, InfUnitRange, OneToInf, PosInfinity, InfIndexRanges
 
-import Infinities: InfiniteCardinal, Infinity
+import Infinities: InfiniteCardinal, Infinity, RealInfinity
 
 import LazyArrays: AbstractCachedMatrix, AbstractCachedVector, AbstractLazyLayout, ApplyArray, ApplyLayout, ApplyMatrix,
                    CachedArray, CachedLayout, CachedMatrix, CachedVector, LazyArrayStyle, LazyLayout,

src/blockbanded/blockbanded.jl

@@ -17,6 +17,7 @@ BlockBandedMatrices.blockbanded_rowstop(A, x::InfiniteCardinal{0}) = x
 
 BlockArrays.blocklasts(a::InfRanges) = Fill(length(a),1)
 
+BlockArrays.findblock(::BlockedOneTo, ::RealInfinity) = Block(ℵ₀)
 
 function BlockArrays.sortedunion(a::Vcat{Int,1,<:Tuple{Union{Int,AbstractVector{Int}},<:AbstractRange}},
                                  b::Vcat{Int,1,<:Tuple{Union{Int,AbstractVector{Int}},<:AbstractRange}})

test/runtests.jl

@@ -6,7 +6,7 @@ import InfiniteLinearAlgebra: qltail, toeptail, tailiterate, tailiterate!, tail_
     BandedToeplitzLayout, PertToeplitzLayout, TridiagonalToeplitzLayout, BidiagonalToeplitzLayout,
     BidiagonalConjugation
 import Base: BroadcastStyle, oneto
-import BlockArrays: _BlockArray, blockcolsupport
+import BlockArrays: _BlockArray, blockcolsupport, findblock
 import BlockBandedMatrices: isblockbanded, _BlockBandedMatrix
 import MatrixFactorizations: QLPackedQ
 import BandedMatrices: bandeddata, _BandedMatrix, BandedStyle
@@ -472,6 +472,10 @@ end
     end
 end
 
+@testset "findblock at +∞, HarmonicOrthogonalPolynomials#88" begin
+    @test findblock(blockedrange(1:2:∞), RealInfinity()) == Block(ℵ₀)
+end
+
 include("test_hessenbergq.jl")
 include("test_infql.jl")
 include("test_infqr.jl")