So, I have a sparse matrix `A`

and a vector `b`

and I want to compute `pinv(A)*b`

.

After reading this post I tried the following:

```
using LinearAlgebra
julia> A = [1 1 1; 2 2 2; 1 0 1]
3×3 Array{Int64,2}:
1 1 1
2 2 2
1 0 1
julia> b = [1,0,0]
3-element Array{Int64,1}:
1
0
0
julia> pinv(A)
3×3 Array{Float64,2}:
-2.22045e-16 2.77556e-17 0.5
0.2 0.4 -1.0
-1.52656e-16 1.66533e-16 0.5
julia> pinv(A)*b
3-element Array{Float64,1}:
-2.220446049250313e-16
0.20000000000000048
-1.5265566588595902e-16
```

Everything is fine up to this point, but when I try the backslash operator i get:

```
julia> qr(A)\b
3-element Array{Float64,1}:
-1.8385868488076965e15
-1.8242825833464351e-16
1.838586848807696e15
```

I’m not sure what happened here. I don’t understand what the result is supposed to be, but clearly it is not `pinv(A)*b`

. Am I using this wrongly or is it a bug?