Move all Real:s during 'evaluate'

Author: asterycs

src/forward.jl

@@ -78,6 +78,10 @@ function evaluate(::Mult, arg1::BinaryOperation{Mult}, arg2::Real)
 end
 
 function evaluate(::Mult, arg1::Real, arg2::BinaryOperation{Mult})
+    if arg1 == 1
+        return arg2
+    end
+
     if arg2.arg1 isa Real
         return BinaryOperation{Mult}(arg1 * arg2.arg1, arg2.arg2)
     elseif arg2.arg2 isa Real
@@ -140,6 +144,10 @@ function evaluate(::Mult, arg1::Monomial, arg2::BinaryOperation{Mult})
 end
 
 function evaluate(::Mult, arg1::BinaryOperation{Mult}, arg2::Monomial)
+    if arg1.arg1 isa Real
+        return BinaryOperation{Mult}(arg1.arg1, BinaryOperation{Mult}(arg1.arg2, arg2))
+    end
+
     is_elementwise = is_elementwise_multiplication(arg1.arg1, arg1.arg2)
     arg1_indices, arg2_indices = get_free_indices.((arg1, arg2))
 
@@ -182,6 +190,16 @@ end
 function evaluate(::Mult, arg1::BinaryOperation{Mult}, arg2::BinaryOperation{Mult})
     if arg1.arg1 == -1 && arg2.arg1 == -1
         return BinaryOperation{Mult}(arg1.arg2, arg2.arg2)
+    elseif arg1.arg1 == -1
+        return BinaryOperation{Mult}(
+            arg1.arg1,
+            evaluate(BinaryOperation{Mult}(arg1.arg2, arg2)),
+        )
+    elseif arg2.arg1 == -1
+        return BinaryOperation{Mult}(
+            arg2.arg1,
+            evaluate(BinaryOperation{Mult}(arg2.arg2, arg1)),
+        )
     end
 
     new_args = []

test/StdTest.jl

@@ -347,8 +347,8 @@ end
     @test to_std_string(gradient(sum(2 * x), x)) == "2vec(1)"
     @test to_std_string(gradient(2 * sum(sin(x)), x)) == "2cos(x)"
     @test to_std_string(gradient(sum(2 * sin(x)), x)) == "2cos(x)"
-    @test to_std_string(gradient(2 * sum(cos(A * x + y)), x)) == "2(-1)Aᵀsin(Ax + y)"
-    @test to_std_string(gradient(sum(2 * cos(A * x + y)), x)) == "2(-1)Aᵀsin(Ax + y)"
+    @test to_std_string(gradient(2 * sum(cos(A * x + y)), x)) == "(-2)Aᵀsin(Ax + y)"
+    @test to_std_string(gradient(sum(2 * cos(A * x + y)), x)) == "(-2)Aᵀsin(Ax + y)"
     @test to_std_string(gradient(sum(x .^ 2), x)) == "2x"
     @test to_std_string(gradient(sum(x .^ 3), x)) == "3x²"
     @test to_std_string(gradient(sum((x + y) .^ 2), x)) == "2(x + y)"
@@ -374,7 +374,7 @@ end
     @matrix A B C X
     @vector x y z
 
-    @test to_std_string(derivative(sum(-y .* (X*z)), X)) == "z(-1)yᵀ"
+    @test to_std_string(derivative(sum(-y .* (X*z)), X)) == "(-1)zyᵀ"
     @test to_std_string(derivative(sum((A .* B) * C * x), x)) == "vec(1)ᵀ(A ⊙ B)C"
 end