It seems like there are missing sparse matrix methods. In both 1.0.2 and 0.7 this code: using SparseArrays using LinearAlgebra A = sprand(10,10,.9) b_dense = Array(sprand(10,1,.8)) # works b_sparse = sprand(10,1,.8) # doesn't work x = A\b_dense # works x = A\b_sparse # doesn't work lu!(A) # gives an error produces these errors: julia> x = A\b_sparse # error ERROR: MethodError: no method matching ldiv!(::SuiteSparse.UMFPACK.UmfpackLU{Float64,Int64}, ::SparseMatrixCSC{Float64,Int64}) and ERROR: MethodError: no method matching lu!(::SparseMatrixCSC{Float64,Int64})

We use the library UMFPACK for solving problems with an asymmetric lhs and unfortunately the library doesn’t support a sparse rhs.

That makes sense, but it seems like the error message could be a bit more user friendly. Also, why does lu!(A) not work for a sparse matrix? The existing error for A\b pointed me to lu!, but lu!() doesn’t work. It seems odd that we can’t factor sparse matrices using the “default” version of lu.

[image] Paul_Hines: Also, why does lu!(A) not work for a sparse matrix? You should use lu(A). lu!(A) means that you want LU factorization in-place, which is not generally possible for sparse matrices.

Missing sparse methods

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Missing sparse methods

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