From 72790c8c1c0eb5faaa25b8c2491fdac087a14a3d Mon Sep 17 00:00:00 2001
From: Bart de Koning <bart.dekoning@deltares.nl>
Date: Sat, 13 Jul 2024 19:08:59 +0200
Subject: [PATCH] Move SparseArrays to weakdeps

---
 Project.toml                               | 4 ++--
 ext/DataInterpolationsChainRulesCoreExt.jl | 3 ++-
 src/DataInterpolations.jl                  | 1 -
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Project.toml b/Project.toml
index d2b21cef..b3bdcfa1 100644
--- a/Project.toml
+++ b/Project.toml
@@ -10,16 +10,16 @@ PrettyTables = "08abe8d2-0d0c-5749-adfa-8a2ac140af0d"
 ReadOnlyArrays = "988b38a3-91fc-5605-94a2-ee2116b3bd83"
 RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
-SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 
 [weakdeps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
 Optim = "429524aa-4258-5aef-a3af-852621145aeb"
 RegularizationTools = "29dad682-9a27-4bc3-9c72-016788665182"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Symbolics = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 
 [extensions]
-DataInterpolationsChainRulesCoreExt = "ChainRulesCore"
+DataInterpolationsChainRulesCoreExt = ["ChainRulesCore", "SparseArrays"]
 DataInterpolationsOptimExt = "Optim"
 DataInterpolationsRegularizationToolsExt = "RegularizationTools"
 DataInterpolationsSymbolicsExt = "Symbolics"
diff --git a/ext/DataInterpolationsChainRulesCoreExt.jl b/ext/DataInterpolationsChainRulesCoreExt.jl
index 30d3fe09..37613347 100644
--- a/ext/DataInterpolationsChainRulesCoreExt.jl
+++ b/ext/DataInterpolationsChainRulesCoreExt.jl
@@ -92,7 +92,8 @@ function ChainRulesCore.rrule(::Type{QuadraticSplineParameterCache}, u, t)
     n = length(u)
 
     Δt = diff(t)
-    diagonal_main = [zero(eltype(Δt)), 2 ./ Δt...]
+    diagonal_main = 2 ./ Δt
+    pushfirst!(diagonal_main, zero(eltype(diagonal_main)))
     diagonal_down = -diagonal_main[2:end]
     diagonal_up = zero(diagonal_down)
     ∂d_∂u = Tridiagonal(diagonal_down, diagonal_main, diagonal_up)
diff --git a/src/DataInterpolations.jl b/src/DataInterpolations.jl
index d5c31598..c86a6579 100644
--- a/src/DataInterpolations.jl
+++ b/src/DataInterpolations.jl
@@ -8,7 +8,6 @@ using LinearAlgebra, RecipesBase
 using PrettyTables
 using ForwardDiff
 using ReadOnlyArrays
-using SparseArrays # Only used in DataInterpolationsChainRulesCoreExt.jl, but otherwise Aqua complains
 import FindFirstFunctions: searchsortedfirstcorrelated, searchsortedlastcorrelated,
                            bracketstrictlymontonic