From 896cf049f433995956773bddbb6e564d4110324c Mon Sep 17 00:00:00 2001
From: Mauro Werder <mauro_lc@runbox.com>
Date: Mon, 8 Jun 2015 22:20:51 +0200
Subject: [PATCH] == for sparse matrices

---
 base/sparse/sparsematrix.jl | 37 ++++++++++++++++++++++++++++++++++++-
 test/sparsedir/sparse.jl    | 25 +++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/base/sparse/sparsematrix.jl b/base/sparse/sparsematrix.jl
index a15c12bebc2cf..c61e5469e70ac 100644
--- a/base/sparse/sparsematrix.jl
+++ b/base/sparse/sparsematrix.jl
@@ -926,7 +926,42 @@ end
 .<{Tv1,Ti1,Tv2,Ti2}(A_1::SparseMatrixCSC{Tv1,Ti1}, A_2::SparseMatrixCSC{Tv2,Ti2}) = broadcast!(<, spzeros( Bool, promote_type(Ti1, Ti2), broadcast_shape(A_1, A_2)...), A_1, A_2)
 .!={Tv1,Ti1,Tv2,Ti2}(A_1::SparseMatrixCSC{Tv1,Ti1}, A_2::SparseMatrixCSC{Tv2,Ti2}) = broadcast!(!=, spzeros( Bool, promote_type(Ti1, Ti2), broadcast_shape(A_1, A_2)...), A_1, A_2)
 
-
+## full equality
+function ==(A1::SparseMatrixCSC, A2::SparseMatrixCSC)
+    size(A1)!=size(A2) && return false
+    vals1, vals2 = nonzeros(A1), nonzeros(A2)
+    rows1, rows2 = rowvals(A1), rowvals(A2)
+    m, n = size(A1)
+    @inbounds for i = 1:n
+        nz1,nz2 = nzrange(A1,i), nzrange(A2,i)
+        j1,j2 = first(nz1), first(nz2)
+        # step through the rows of both matrices at once:
+        while j1<=last(nz1) && j2<=last(nz2)
+            r1,r2 = rows1[j1], rows2[j2]
+            if r1==r2
+                vals1[j1]!=vals2[j2] && return false
+                j1+=1
+                j2+=1
+            else
+                if r1<r2
+                    vals1[j1]!=0 && return false
+                    j1+=1
+                else
+                    vals2[j2]!=0 && return false
+                    j2+=1
+                end
+            end
+        end
+        # finish off any left-overs:
+        for j = j1:last(nz1)
+            vals1[j]!=0 && return false
+        end
+        for j = j2:last(nz2)
+            vals2[j]!=0 && return false
+        end
+    end
+    return true
+end
 
 ## Reductions
 
diff --git a/test/sparsedir/sparse.jl b/test/sparsedir/sparse.jl
index 1475ad14ee6df..62f826d631142 100644
--- a/test/sparsedir/sparse.jl
+++ b/test/sparsedir/sparse.jl
@@ -968,3 +968,28 @@ A[3,1] = 2
 A.nzval[2] = 0.0
 @test ishermitian(A) == true
 @test issym(A) == true
+
+# equality ==
+A1 = speye(10)
+A2 = speye(10)
+nonzeros(A1)[end]=0
+@test A1!=A2
+nonzeros(A1)[end]=1
+@test A1==A2
+A1[1:4,end] = 1
+@test A1!=A2
+nonzeros(A1)[end-4:end-1]=0
+@test A1==A2
+A2[1:4,end-1] = 1
+@test A1!=A2
+nonzeros(A2)[end-5:end-2]=0
+@test A1==A2
+A2[2:3,1] = 1
+@test A1!=A2
+nonzeros(A2)[2:3]=0
+@test A1==A2
+A1[2:5,1] = 1
+@test A1!=A2
+nonzeros(A1)[2:5]=0
+@test A1==A2
+@test sparse([1,1,0])!=sparse([0,1,1])