From 9ed83402d3fae142f268ff3ddcd1fe3bac19f760 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Tue, 28 Jan 2025 20:19:51 +0000
Subject: [PATCH] + and - for DiagTrav (#142)

* + and - for DiagTrav

* overload /, \ and - for DiagTrav
---
 Project.toml           |  2 +-
 src/blockkron.jl       | 13 +++++++++++++
 test/test_blockkron.jl | 14 ++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 9ec09bd..115061c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "LazyBandedMatrices"
 uuid = "d7e5e226-e90b-4449-9968-0f923699bf6f"
 authors = ["Sheehan Olver <solver@mac.com>"]
-version = "0.11.2"
+version = "0.11.3"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
diff --git a/src/blockkron.jl b/src/blockkron.jl
index 4c511d3..6f85db0 100644
--- a/src/blockkron.jl
+++ b/src/blockkron.jl
@@ -212,6 +212,19 @@ end
 invdiagtrav(a) = InvDiagTrav(a)
 invdiagtrav(a::DiagTrav) = a.array
 
+-(A::DiagTrav) = DiagTrav(-A.array)
+
+for op in (:+, :-)
+    @eval $op(A::DiagTrav, B::DiagTrav) = DiagTrav($op(A.array, B.array))
+end
+
+for op in (:*, :/)
+    @eval $op(A::DiagTrav, k::Number) = DiagTrav($op(A.array, k))
+end
+
+for op in (:*, :\)
+    @eval $op(k::Number, A::DiagTrav) = DiagTrav($op(k, A.array))
+end
 
 """
     KronTrav(A,B,C...)
diff --git a/test/test_blockkron.jl b/test/test_blockkron.jl
index 3e589ea..9bbd321 100644
--- a/test/test_blockkron.jl
+++ b/test/test_blockkron.jl
@@ -34,6 +34,20 @@ LinearAlgebra.factorize(A::MyLazyArray) = factorize(A.data)
         A = [1 2; 3 4; 5 6]
         @test DiagTrav(A) == [1, 3, 2, 5, 4]
 
+        @test DiagTrav(A) + DiagTrav(A) isa DiagTrav
+        @test DiagTrav(A) - DiagTrav(A) isa DiagTrav
+        @test 2DiagTrav(A) isa DiagTrav
+        @test 2\DiagTrav(A) isa DiagTrav
+        @test DiagTrav(A)*2 isa DiagTrav
+        @test DiagTrav(A)/2 isa DiagTrav
+        @test -DiagTrav(A) isa DiagTrav
+
+
+        @test DiagTrav(A) + DiagTrav(A) == 2DiagTrav(A) == DiagTrav(A)*2 == 2Vector(DiagTrav(A))
+        @test DiagTrav(A) - DiagTrav(A) == 0DiagTrav(A) == 0Vector(DiagTrav(A))
+        @test 2\DiagTrav(A) == DiagTrav(A)/2 == Vector(DiagTrav(A))/2
+        @test -DiagTrav(A) == -Vector(DiagTrav(A))
+
         @test resize!(DiagTrav(A), Block(2)) == [1, 3,2]
 
         A = DiagTrav(randn(3,3,3))