Add (sp)diagm pair constructors (#408)

* Add (sp)diagm pair constructors

README.md

@@ -180,6 +180,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `*(::Union{Char,AbstractString},::Union{Char,AbstractString})` concatenation. ([#22512])
 
+* `diagm` and `spdiagm` accept pairs mapping diagonals to vectors ([#24047], [#23757])
+
 ## Renaming
 
 
@@ -347,6 +349,8 @@ includes this fix. Find the minimum version from there.
 [#23570]: https://github.com/JuliaLang/julia/issues/23570
 [#23666]: https://github.com/JuliaLang/julia/issues/23666
 [#23667]: https://github.com/JuliaLang/julia/issues/23667
+[#23757]: https://github.com/JuliaLang/julia/issues/23757
 [#23812]: https://github.com/JuliaLang/julia/issues/23812
 [#23931]: https://github.com/JuliaLang/julia/issues/23931
+[#24047]: https://github.com/JuliaLang/julia/issues/24047
 [#24282]: https://github.com/JuliaLang/julia/issues/24282

src/Compat.jl

@@ -736,6 +736,33 @@ end
     export textwidth
 end
 
+# 0.7.0-DEV.2116
+@static if VERSION < v"0.7.0-DEV.2116"
+    import Base: spdiagm
+    function spdiagm(kv::Pair...)
+        I, J, V = Base.SparseArrays.spdiagm_internal(last.(kv), first.(kv))
+        m = max(Base.SparseArrays.dimlub(I), Base.SparseArrays.dimlub(J))
+        return sparse(I, J, V, m, m)
+    end
+end
+
+# 0.7.0-DEV.2161
+@static if VERSION < v"0.7.0-DEV.2161"
+    import Base: diagm
+    function diagm(kv::Pair...)
+        T = promote_type(map(x -> eltype(x.second), kv)...)
+        n = mapreduce(x -> length(x.second) + abs(x.first), max, kv)
+        A = zeros(T, n, n)
+        for p in kv
+            inds = diagind(A, p.first)
+            for (i, val) in enumerate(p.second)
+                A[inds[i]] += val
+            end
+        end
+        return A
+    end
+end
+
 include("deprecated.jl")
 
 end # module Compat

test/runtests.jl

@@ -867,6 +867,12 @@ end
 @test textwidth("A") == 1
 @test textwidth('A') == 1
 
+# 0.7
+@test diagm(0 => ones(2), -1 => ones(2)) == [1.0 0.0 0.0; 1.0 1.0 0.0; 0.0 1.0 0.0]
+@test diagm(0 => ones(2), 1 => ones(2)) == [1.0 1.0 0.0; 0.0 1.0 1.0; 0.0 0.0 0.0]
+@test spdiagm(0 => ones(2), -1 => ones(2)) == [1.0 0.0 0.0; 1.0 1.0 0.0; 0.0 1.0 0.0]
+@test spdiagm(0 => ones(2), 1 => ones(2)) == [1.0 1.0 0.0; 0.0 1.0 1.0; 0.0 0.0 0.0]
+
 if VERSION < v"0.6.0"
     include("deprecated.jl")
 end