Multiplication of IntervalBox by a matrix (#253)

* Add multiplication of an IntervalBox by a matrix

* Missing end

* Fix testset

Author: dpsanders

src/multidim/arithmetic.jl

@@ -29,7 +29,7 @@ Base.size(X::IntervalBox{2,Float64}) = (2,)
 @inline broadcasted(f, x, Y::IntervalBox) = wrap(f.(x, Y.v))
  # for literal_pow:
 @inline broadcasted(f, x, y, Z::IntervalBox) = wrap(f.(x, y, Z.v))
-@inline broadcasted(f, x, Y::IntervalBox, z) = wrap(f.(x, Y.v, z)) 
+@inline broadcasted(f, x, Y::IntervalBox, z) = wrap(f.(x, Y.v, z))
 
 for op in (:+, :-, :∩, :∪, :⊆, :isinterior, :dot, :setdiff, :×)
     @eval $(op)(a::SVector, b::IntervalBox) = $(op)(IntervalBox(a), b)
@@ -38,3 +38,8 @@ end
 for op in (:+, :-, :∩, :∪, :⊆, :isinterior, :dot, :setdiff, :×)
     @eval $(op)(a::IntervalBox, b::SVector) = $(op)(a, IntervalBox(b))
 end
+
+
+# multiplication by a matrix
+
+*(A::AbstractMatrix, X::IntervalBox) = IntervalBox(A * X.v)

test/multidim_tests/multidim.jl

@@ -236,4 +236,16 @@ end
 
 end
 
+@testset "Multiplication by a matrix" begin
+    A = [1 2; 3 4]
+    X = IntervalBox(1..2, 3..4)
+
+    @test A * X == IntervalBox(7..10, 15..22)
+
+    B = SMatrix{2,2}(A)
+
+    @test B * X == IntervalBox(7..10, 15..22)
+
+end
+
 end