From ffc9778ec2ae34550629a8530ed04922a41a5864 Mon Sep 17 00:00:00 2001
From: Andreas Noack <andreasnoackjensen@gmail.com>
Date: Fri, 16 Jan 2015 16:15:03 -0500
Subject: [PATCH] Fix #6838. Add setindex! for triangular matrix types.

---
 base/linalg/triangular.jl |  5 +++++
 test/linalg/triangular.jl | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/base/linalg/triangular.jl b/base/linalg/triangular.jl
index b0658b1029e3f..2ec3bb7881da7 100644
--- a/base/linalg/triangular.jl
+++ b/base/linalg/triangular.jl
@@ -108,6 +108,11 @@ getindex{T,S}(A::LowerTriangular{T,S}, i::Integer, j::Integer) = i >= j ? A.data
 getindex{T,S}(A::UnitUpperTriangular{T,S}, i::Integer, j::Integer) = i == j ? one(T) : (i < j ? A.data[i,j] : zero(A.data[i,j]))
 getindex{T,S}(A::UpperTriangular{T,S}, i::Integer, j::Integer) = i <= j ? A.data[i,j] : zero(A.data[i,j])
 
+setindex!(A::UpperTriangular, x, i::Integer, j::Integer) = i <= j ? (A.data[i,j] = x; A) : throw(BoundsError())
+setindex!(A::UnitUpperTriangular, x, i::Integer, j::Integer) = i < j ? (A.data[i,j] = x; A) : throw(BoundsError())
+setindex!(A::LowerTriangular, x, i::Integer, j::Integer) = i >= j ? (A.data[i,j] = x; A) : throw(BoundsError())
+setindex!(A::UnitLowerTriangular, x, i::Integer, j::Integer) = i > j ? (A.data[i,j] = x; A) : throw(BoundsError())
+
 istril{T,S}(A::LowerTriangular{T,S}) = true
 istril{T,S}(A::UnitLowerTriangular{T,S}) = true
 istril{T,S}(A::UpperTriangular{T,S}) = false
diff --git a/test/linalg/triangular.jl b/test/linalg/triangular.jl
index 785a6c3dbb16a..1d9fa1ed18bbf 100644
--- a/test/linalg/triangular.jl
+++ b/test/linalg/triangular.jl
@@ -48,11 +48,41 @@ for elty1 in (Float32, Float64, Complex64, Complex128, BigFloat, Int)
                     # similar
                     @test isa(similar(A1), t1)
 
-                    # Linear indexing
+                    # getindex
+                    ## Linear indexing
                     for i = 1:length(A1)
                         @test A1[i] == full(A1)[i]
                     end
 
+                    ## Cartesian indexing
+                    for i = 1:size(A1, 1)
+                        for j = 1:size(A1, 2)
+                            @test A1[i,j] == full(A1)[i,j]
+                        end
+                    end
+
+                    # setindex! (and copy)
+                    A1c = copy(A1)
+                    for i = 1:size(A1, 1)
+                        for j = 1:size(A1, 2)
+                            if uplo1 == :U
+                                if i > j || (i == j && t1 == UnitUpperTriangular)
+                                    @test_throws BoundsError A1c[i,j] = 0
+                                else
+                                    A1c[i,j] = 0
+                                    @test A1c[i,j] == 0
+                                end
+                            else
+                                if i < j || (i == j && t1 == UnitLowerTriangular)
+                                    @test_throws BoundsError A1c[i,j] = 0
+                                else
+                                    A1c[i,j] = 0
+                                    @test A1c[i,j] == 0
+                                end
+                            end
+                        end
+                    end
+
                     # istril/istriu
                     if uplo1 == :L
                         @test istril(A1)