Merge pull request #570 from JuliaSymbolics/s/fix-diff-error2

Fix one more wrong error in array differentiation
JuliaSymbolics · Apr 7, 2022 · 17b9aa5 · 17b9aa5
2 parents 8494959 + c7971ac
commit 17b9aa5
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/src/diff.jl b/src/diff.jl
@@ -73,6 +73,11 @@ function occursin_info(x, expr)
         !occursin(first(arguments(x)), first(arguments(expr)))
         return false
     end
+
+    if is_scalar_indexed(expr) && !is_scalar_indexed(x) && !occursin(x, expr)
+        return false
+    end
+
     !istree(expr) && return false
     if isequal(x, expr)
         true

diff --git a/test/diff.jl b/test/diff.jl
@@ -299,8 +299,10 @@ end
 
 # make sure derivative(x[1](t), y) does not fail
 let
-    @variables t
+    @variables t a(t)
     vars = collect(@variables(x[1:1](t))[1])
     ps = collect(@variables(ps[1:1])[1])
     @test Symbolics.derivative(ps[1], vars[1]) == 0
+    @test Symbolics.derivative(ps[1], a) == 0
+    @test Symbolics.derivative(x[1], a) == 0
 end