Merge pull request #458 from JuliaSymbolics/s/fix-broadcast-single

fix extruded dim in broadcast when all args have size 1

src/array-lib.jl

@@ -125,9 +125,19 @@ function Broadcast.materialize(bc::Broadcast.Broadcasted{SymBroadcast})
     ndim = mapfoldl(ndims, max, bc.args, init=0)
     subscripts = makesubscripts(ndim)
 
+    onedim_count = mapreduce(+, bc.args) do x
+        if ndims(x) != 0
+            map(i-> isonedim(x, i) ? 1 : 0, 1:ndim)
+        else
+            map(i-> 1, 1:ndim)
+        end
+    end
+
+    extruded = map(x->x < length(bc.args), onedim_count)
+
     expr_args′ = map(bc.args) do x
         if ndims(x) != 0
-            subs = map(i-> isonedim(x, i) ?
+            subs = map(i-> extruded[i] && isonedim(x, i) ?
                        1 : subscripts[i], 1:ndims(x))
             x[subs...]
         else

src/arrays.jl

@@ -627,7 +627,7 @@ function scalarize(arr::ArrayOp, idx)
     contracted = setdiff(iidx, arr.output_idx)
 
     dict = Dict(oi => (unwrap(i) isa Symbolic ? unwrap(i) : axs[oi][i])
-                for (oi, i) in zip(arr.output_idx, idx))
+                for (oi, i) in zip(arr.output_idx, idx) if unwrap(oi) isa Symbolic)
     partial = replace_by_scalarizing(arr.expr, dict)
 
     axes = [axs[c] for c in contracted]

test/arrays.jl

@@ -46,7 +46,7 @@ end
 
 getdef(v) = getmetadata(v, Symbolics.VariableDefaultValue)
 @testset "broadcast & scalarize" begin
-    @variables A[1:5,1:3]=42 b[1:3]=[2, 3, 5] t x[1:4](t)
+    @variables A[1:5,1:3]=42 b[1:3]=[2, 3, 5] t x[1:4](t) u[1:1]
     AA = Symbolics.scalarize(A)
     bb = Symbolics.scalarize(b)
     @test all(isequal(42), getdef.(AA))
@@ -66,6 +66,12 @@ getdef(v) = getmetadata(v, Symbolics.VariableDefaultValue)
     D = Differential(t)
     @test isequal(collect(D.(x) ~ x), map(i->D(x[i]) ~ x[i], eachindex(x)))
     @test_throws ArgumentError A ~ t
+
+    # #448
+    @test isequal(Symbolics.scalarize(u + u), [2u[1]])
+
+    # #417
+    @test isequal(Symbolics.scalarize(x', (1,1)), x[1])
 end
 
 @testset "Parent" begin