Fix non-square sparse views

Fixes #287

Author: ChrisRackauckas

src/factorization.jl

@@ -6,6 +6,10 @@ function _ldiv!(x::Vector, A::Factorization, b::Vector)
     ldiv!(A, x)
 end
 
+function _ldiv!(x::AbstractVector, A::SparseArrays.SPQR.QRSparse, b::AbstractVector)
+    x .= A \ b
+end
+
 function SciMLBase.solve(cache::LinearCache, alg::AbstractFactorization; kwargs...)
     if cache.isfresh
         fact = do_factorization(alg, cache.A, cache.b, cache.u)

test/nonsquare.jl

@@ -24,3 +24,9 @@ b = rand(n)
 prob = LinearProblem(A, b)
 res = Matrix(A) \ b
 @test solve(prob, KrylovJL_CRAIGMR()) ≈ res
+
+A = sprandn(1000, 100, 0.1)
+b = randn(1001)
+prob = LinearProblem(A, view(b, 1:1000))
+linsolve = init(prob, QRFactorization())
+solve(linsolve)