From 48f2f4d28fe0e07e91bad9b48b3378f40849699c Mon Sep 17 00:00:00 2001
From: Chris Rackauckas <accounts@chrisrackauckas.com>
Date: Tue, 16 Jul 2019 21:30:06 -0400
Subject: [PATCH] don't use recursive factorization if can't setindex

---
 src/init.jl             | 3 +++
 src/linear_nonlinear.jl | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/init.jl b/src/init.jl
index c7f521faf..5ead31b04 100644
--- a/src/init.jl
+++ b/src/init.jl
@@ -1,5 +1,6 @@
 value(x) = x
 cuify(x) = error("To use LinSolveGPUFactorize, you must do `using CuArrays`")
+can_setindex(x) = true
 
 function __init__()
   @require ApproxFun="28f2ccd6-bb30-5033-b560-165f7b14dc2f" begin
@@ -88,6 +89,8 @@ function __init__()
     value(x::Flux.Tracker.TrackedReal)  = x.data
     value(x::Flux.Tracker.TrackedArray) = x.data
 
+    can_setindex(x::Flux.Tracker.TrackedArray) = false
+
     # Support adaptive with non-tracked time
     @inline function ODE_DEFAULT_NORM(u::Flux.Tracker.TrackedArray,t) where {N}
       sqrt(sum(x->ODE_DEFAULT_NORM(x[1],x[2]),zip((value(x) for x in u),Iterators.repeated(t))) / length(u))
diff --git a/src/linear_nonlinear.jl b/src/linear_nonlinear.jl
index 80cf9913a..0b98c77a0 100644
--- a/src/linear_nonlinear.jl
+++ b/src/linear_nonlinear.jl
@@ -53,7 +53,7 @@ function (p::DefaultLinSolve)(x,A,b,update_matrix=false;tol=nothing, kwargs...)
   if update_matrix
     if typeof(A) <: Matrix
       blasvendor = BLAS.vendor()
-      if (blasvendor === :openblas || blasvendor === :openblas64) && size(A,1) <= 500 # if the user doesn't use OpenBLAS, we assume that is a much better BLAS implementation like MKL
+      if (blasvendor === :openblas || blasvendor === :openblas64) && size(A,1) <= 500 && can_setindex(x) # if the user doesn't use OpenBLAS, we assume that is a much better BLAS implementation like MKL
         p.A = RecursiveFactorization.lu!(A)
       else
         p.A = lu!(A)