From 1f88c8667fbf1e0de23eaee5ab16fe48ec35b4ac Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Tue, 28 Apr 2026 06:17:38 -0500
Subject: [PATCH] Add missing methods: ==, hash, show

Co-authored-by: Copilot <copilot@github.com>
---
 src/FactoredMatrices.jl | 15 +++++++++++----
 test/runtests.jl        |  8 +++++++-
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/FactoredMatrices.jl b/src/FactoredMatrices.jl
index 946df3f..fd2b49d 100644
--- a/src/FactoredMatrices.jl
+++ b/src/FactoredMatrices.jl
@@ -1,7 +1,7 @@
 module FactoredMatrices
 
 using LinearAlgebra
-import Base: *, Array, size, length, getindex, similar, adjoint, transpose
+import Base: *, Array, Matrix, size, length, similar, ==, hash, adjoint, transpose
 import LinearAlgebra: mul!, dot
 
 export FactoredMatrix
@@ -78,6 +78,15 @@ similar(::FactoredMatrix, T, dims) = Array{T}(undef, dims)
 length(A::FactoredMatrix) = size(A.U, 1) * size(A.V, 2)
 
 Array(A::FactoredMatrix) = A.U * A.V
+Matrix(A::FactoredMatrix) = Array(A)
+
+==(A::FactoredMatrix, B::FactoredMatrix) = A.U == B.U && A.V == B.V
+const FMhash = Int === Int64 ? 0x99ac4c2c56e5bd6e : 0x70c3ac8c
+hash(A::FactoredMatrix, h::UInt) = hash(A.U, hash(A.V, hash(FMhash, h)))
+
+function Base.show(io::IO, A::FactoredMatrix)
+    print(io, "FactoredMatrix of size ", size(A), " with rank ", size(A.U, 2))
+end
 
 adjoint(A::FactoredMatrix{T}) where T = FactoredMatrix{T}(adjoint(A.V), adjoint(A.U))
 transpose(A::FactoredMatrix{T}) where T = FactoredMatrix{T}(transpose(A.V), transpose(A.U))
@@ -214,9 +223,7 @@ end
 
 # --- Queries ---
 
-function LinearAlgebra.issymmetric(A::FactoredMatrix)
-    size(A.U, 1) == size(A.V, 2) && A.U == A.V'
-end
+LinearAlgebra.issymmetric(A::FactoredMatrix) = A.U == A.V'
 
 function dot(A::FactoredMatrix, B::FactoredMatrix)
     M1 = B.U' * A.U
diff --git a/test/runtests.jl b/test/runtests.jl
index 7edae70..fe7a579 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -32,8 +32,14 @@ end
         U = myrand(T, 15, 3)
         V = myrand(T, 3, 10)
         Mf = FactoredMatrix(U, V)
-        M = Array(Mf)
+        M = Matrix(Mf)
         @test M == U*V
+        @test M == Array(Mf)
+        Mf2 = FactoredMatrix(copy(U), copy(V))
+        @test Mf == Mf2
+        @test hash(Mf) == hash(Mf2)
+        @test hash(Mf) != hash(U, hash(V))  # we can distinguish the hash of the wrapped object from its component parts
+        @test sprint(show, Mf) == "FactoredMatrix of size (15, 10) with rank 3"
         # lowercase adjoint(Mf) and transpose(Mf) re-wrap `U` and `V`
         @test Mf' isa FactoredMatrix{T}
         @test transpose(Mf) isa FactoredMatrix{T}