Don't error in lmul!/rmul! with non-zero entries (#171)

* Don't error in lmul!/rmul! with non-zero entries

* add tests

Author: dlfivefifty

Project.toml

@@ -1,6 +1,6 @@
 name = "BlockBandedMatrices"
 uuid = "ffab5731-97b5-5995-9138-79e8c1846df0"
-version = "0.12.5"
+version = "0.12.6"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"

src/broadcast.jl

@@ -250,17 +250,13 @@ end
 
 
 function blockbanded_rmul!(B::AbstractMatrix{T}, x::Number) where T
-    x == zero(T) || throw(BandError(B))
-
     for J = blockaxes(B,2), K = blockcolsupport(B,J)
         rmul!(view(B,K,J), x)
     end
     B
 end
 
 function blockbanded_lmul!(x::Number, B::AbstractMatrix{T}) where T
-    x == zero(T) || throw(BandError(B))
-
     for J = blockaxes(B,2), K = blockcolsupport(B,J)
         lmul!(x, view(B,K,J))
     end

test/test_linalg.jl

@@ -18,6 +18,16 @@ import BlockBandedMatrices: _BandedBlockBandedMatrix, MemoryLayout, mul!,
     C.data .= NaN
     rmul!(C, 0.0)
     norm(C) == 0.0
+
+    C.data .= 1
+    @test lmul!(2, C) == fill(2,3,3)
+
+    A = BlockBandedMatrix{Float64}(undef, 1:2,1:2, (1,1))
+    A.data .= 1
+    lmul!(2, A)
+    @test A == fill(2,3,3)
+    rmul!(A, 2)
+    @test A == fill(4,3,3)
 end
 
 @testset "BlockBandedMatrix linear algebra" begin