Merge pull request #204 from JuliaReach/schillic/203

#203 - fix scalar multiplication of a LinearMap
JuliaReach · Jan 29, 2018 · f9d638f · f9d638f
2 parents ccccf40 + 850eede
commit f9d638f
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Showing 2 changed files with 25 additions and 3 deletions.
diff --git a/src/LinearMap.jl b/src/LinearMap.jl
@@ -23,15 +23,15 @@ LinearMap(M::AbstractMatrix{N}, map::LinearMap{N, S}
 
 """
 ```
-    *(M::AbstractMatrix{<:Real}, S::LazySet)
+    *(M::AbstractMatrix{<:Real}, X::LazySet)
 ```
 
 Return the linear map of a convex set.
 
 ### Input
 
 - `M` -- matrix/linear map
-- `S` -- convex set
+- `X` -- convex set
 
 ### Output
 
@@ -56,7 +56,7 @@ Return a linear map of a convex set by a scalar value.
 ### Input
 
 - `a` -- real scalar
-- `S` -- convex set
+- `X` -- convex set
 
 ### Output
 
@@ -66,6 +66,26 @@ function *(a::N, X::S)::LinearMap{N, S} where {S<:LazySet{N}} where {N<:Real}
     return LinearMap(a * speye(N, dim(X)), X)
 end
 
+"""
+```
+    *(a::N, map::S)::S where {S<:LinearMap{N, S}} where {N<:Real}
+```
+
+Return a linear map scaled by a scalar value.
+
+### Input
+
+- `a` -- real scalar
+- `map` -- linear map
+
+### Output
+
+The scaled linear map.
+"""
+function *(a::N, map::S)::S where {S<:LinearMap{N, T}} where {N<:Real} where {T}
+    return LinearMap(a * map.M, map.sf)
+end
+
 """
 ```
     *(M::AbstractMatrix, Z::ZeroSet)

diff --git a/test/unit_LinearMap.jl b/test/unit_LinearMap.jl
@@ -33,6 +33,8 @@ for N in [Float64, Rational{Int}, Float32]
     # scalar multiplication
     b = BallInf(N[0., 0.], N(1.))
     lm = N(2.) * b
+    # repeated scalar multiplication
+    lm2 = N(2.) * lm
     # Test Dimension
     @test dim(lm) == 2
     # Test Support Vector