From c8b68a8b0930cc4485f56615edaa9649851b23eb Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Sun, 7 Apr 2024 17:41:26 +0200
Subject: [PATCH] Support caching AbstractQ (#298)

---
 Project.toml       |  2 +-
 src/cache.jl       | 19 ++++++++++++++++---
 test/cachetests.jl | 10 +++++++++-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/Project.toml b/Project.toml
index cbb0d4d5..62b272f6 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "LazyArrays"
 uuid = "5078a376-72f3-5289-bfd5-ec5146d43c02"
-version = "1.9.0"
+version = "1.9.1"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
diff --git a/src/cache.jl b/src/cache.jl
index 07fa5cba..0fa3b5ad 100644
--- a/src/cache.jl
+++ b/src/cache.jl
@@ -5,11 +5,11 @@ const AbstractCachedVector{T} = AbstractCachedArray{T,1}
 const AbstractCachedMatrix{T} = AbstractCachedArray{T,2}
 
 
-mutable struct CachedArray{T,N,DM<:AbstractArray{T,N},M<:AbstractArray{T,N}} <: AbstractCachedArray{T,N}
+mutable struct CachedArray{T,N,DM<:AbstractArray{T,N},M} <: AbstractCachedArray{T,N}
     data::DM
     array::M
     datasize::NTuple{N,Int}
-    function CachedArray{T,N,DM,M}(data::DM, array::M, datasize::NTuple{N,Int}) where {T,N,DM<:AbstractArray{T,N},M<:AbstractArray{T,N}}
+    function CachedArray{T,N,DM,M}(data::DM, array::M, datasize::NTuple{N,Int}) where {T,N,DM<:AbstractArray{T,N},M}
         for d in datasize
             d < 0 && throw(ArgumentError("Datasize must be 0 or more"))
         end
@@ -26,7 +26,7 @@ function CachedArray(data::AbstractArray{T,N}, array::AbstractArray{V,N}, datasi
 end
 
 const CachedVector{T,DM<:AbstractVector{T},M<:AbstractVector{T}} = CachedArray{T,1,DM,M}
-const CachedMatrix{T,DM<:AbstractMatrix{T},M<:AbstractMatrix{T}} = CachedArray{T,2,DM,M}
+const CachedMatrix{T,DM<:AbstractMatrix{T},M} = CachedArray{T,2,DM,M}
 
 
 
@@ -539,3 +539,16 @@ function cacheddata(V::SubArray)
     data = cacheddata(P)
     view(data, intersect.(axes(data), parentindices(V))...)
 end
+
+
+##
+# AbstractQ
+##
+cache(A::AbstractQ) = _cache(MemoryLayout(A), A)
+_cache(_, O::AbstractQ) = CachedArray(O)
+CachedArray(array::AbstractQ{T}) where T = CachedArray(similar(Matrix{T}, (0,0)), array)
+CachedArray(data::AbstractMatrix, array::AbstractQ) = CachedArray(data, array, size(data))
+CachedArray(data::AbstractMatrix{T}, array::AbstractQ{T}, datasize::NTuple{2,Int}) where T =
+    CachedMatrix{T,typeof(data),typeof(array)}(data, array, datasize)
+
+length(A::CachedMatrix{<:T,<:AbstractMatrix{T},<:AbstractQ{T}}) where T = prod(size(A.array))
\ No newline at end of file
diff --git a/test/cachetests.jl b/test/cachetests.jl
index cefe6a79..f3f6c941 100644
--- a/test/cachetests.jl
+++ b/test/cachetests.jl
@@ -1,6 +1,7 @@
 module CacheTests
 
-using LazyArrays, FillArrays, LinearAlgebra, ArrayLayouts, StaticArrays, SparseArrays, Test
+using LazyArrays, FillArrays, LinearAlgebra, ArrayLayouts, SparseArrays, Test
+using StaticArrays
 import LazyArrays: CachedArray, CachedMatrix, CachedVector, PaddedLayout, CachedLayout, resizedata!, zero!,
                     CachedAbstractArray, CachedAbstractVector, CachedAbstractMatrix, AbstractCachedArray, AbstractCachedMatrix
 
@@ -435,6 +436,13 @@ using Infinities
         @test  A'[1:3] == A.array'[1:3]
         @test  A'[1:11] == A.array'[1:11]
     end
+
+    @testset "AbstractQ" begin
+        Q = qr(randn(5,5)).Q
+        C = cache(Q);
+        @test C[1:5,1:5] == Q[1:5,1:5]
+        @test length(C) == 25        
+    end
 end
 
 end # module