Add (sp)diagm pair constructors

[ararslan]

No description provided.

[fredrikekre]

I think we need something like:

# 0.7.0-DEV.2116
@static if VERSION < v"0.7.0-DEV.2116"
    Base.spdiagm(kv::Pair...) = spdiagm(last.(kv), first.(kv))
end

# 0.7.0-DEV.2161
@static if VERSION < v"0.7.0-DEV.2161"
    function Base.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

[ararslan]

Ah, looks like the tests will need to be adjusted. I guess some sparse/dense equality stuff is 0.7 only?

[fredrikekre]

Ah, looks like the tests will need to be adjusted. I guess some sparse/dense equality stuff is 0.7 only?

No, the difference is that spdiagm always return a square matrix on 0.7, which diagm has always done, so my code up there is wrong. I can fix up this PR later.

[ararslan]

Looks like the Travis failures are now that their macOS images are having issues. Thanks for your help here!

[fredrikekre]

failures are JuliaLang/julia#24658