fix conj (#417)

* fix `conj`

* improve wording

Author: ericphanson

NEWS.md

@@ -1,3 +1,7 @@
+# Changes in v0.14.1
+
+* there was a bug causing `conj` to act in-place (reported in [#416](https://github.com/jump-dev/Convex.jl/issues/416)), which has been fixed ([#417](https://github.com/jump-dev/Convex.jl/pull/417)). This bug appears to have existed since the introduction of `conj` in Convex.jl v0.5.0.
+
 # Changes in v0.14.0
 
 ## Breaking changes

Project.toml

@@ -1,6 +1,6 @@
 name = "Convex"
 uuid = "f65535da-76fb-5f13-bab9-19810c17039a"
-version = "0.14.0"
+version = "0.14.1"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

src/atoms/affine/conjugate.jl

@@ -30,12 +30,13 @@ end
 function conic_form!(x::ConjugateAtom, unique_conic_forms::UniqueConicForms)
     if !has_conic_form(unique_conic_forms, x)
         objective = conic_form!(x.children[1], unique_conic_forms)
+        new_obj = ConicObj()
         for var in keys(objective)
             x1 = conj(objective[var][1])
             x2 = conj(objective[var][2])
-            objective[var] = (x1,x2)
+            new_obj[var] = (x1,x2)
         end
-        cache_conic_form!(unique_conic_forms, x, objective)
+        cache_conic_form!(unique_conic_forms, x, new_obj)
     end
     return get_conic_form(unique_conic_forms, x)
 end

test/definitions.jl

@@ -14,3 +14,12 @@ end
     hvar.value = h
     @test evaluate(conv(hvar, x)) ≈ _conv(h, x)
 end
+
+
+@testset "`conj` (issue #416)" begin
+    A = [1 1im; -1im 1]
+    X = ComplexVariable(2, 2)
+    p = minimize(real(tr(conj(X))), [X == A])
+    solve!(p, () -> SCS.Optimizer(verbose=1, eps=1e-6))
+    @test evaluate(X) ≈ A atol=1e-3
+end