Add diagm(), fix #62

Author: Andy Ferris

src/StaticArrays.jl

@@ -6,7 +6,7 @@ import Base: @pure, @propagate_inbounds, getindex, setindex!, size, similar,
              length, convert, promote_op, map, map!, reduce, mapreduce,
              broadcast, broadcast!, conj, transpose, ctranspose, hcat, vcat,
              ones, zeros, eye, cross, vecdot, reshape, fill, fill!, det, inv,
-             eig, trace, vecnorm, norm, dot
+             eig, trace, vecnorm, norm, dot, diagm
 
 export StaticScalar, StaticArray, StaticVector, StaticMatrix
 export Scalar, SArray, SVector, SMatrix

src/linalg.jl

@@ -242,6 +242,16 @@ end
     end
 end
 
+@generated function diagm(v::StaticVector)
+    T = eltype(v)
+    exprs = [i == j ? :(v[$i]) : zero(T) for i = 1:length(v), j = 1:length(v)]
+    newtype = similar_type(v, (length(v), length(v)))
+    return quote
+        $(Expr(:meta, :inline))
+        @inbounds return $(Expr(:call, newtype, Expr(:tuple, exprs...)))
+    end
+end
+
 @generated function cross(a::StaticVector, b::StaticVector)
     if length(a) === 3 && length(b) === 3
         return quote

test/linalg.jl

@@ -14,6 +14,10 @@
         @test v1 - v2 === @SVector [-2, 1, 4, 7]
     end
 
+    @testset "diagm()" begin
+        @test diagm(SVector(1,2)) === @SMatrix [1 0; 0 2]
+    end
+
     @testset "eye()" begin
         @test eye(SMatrix{2,2,Int}) === @SMatrix [1 0; 0 1]
         @test eye(SMatrix{2,2}) === @SMatrix [1.0 0.0; 0.0 1.0]