function

src/solver/postprocess.jl

@@ -104,26 +104,8 @@ function _postprocess_root(x::SymbolicUtils.BasicSymbolic)
         end
     end
 
-    opers = [acos, asin, atan]
-    exacts = [0, Symbolics.term(*, pi), Symbolics.term(/,pi,3),
-        Symbolics.term(/, pi, 2),
-        Symbolics.term(/, Symbolics.term(*, 2, pi), 3),
-        Symbolics.term(/, pi, 6),
-        Symbolics.term(/, Symbolics.term(*, 5, pi), 6),
-        Symbolics.term(/, pi, 4)
-    ]
-
-    if any(isequal(oper, o) for o in opers) && isempty(Symbolics.get_variables(x))
-        val = eval(Symbolics.toexpr(x))
-        for i in eachindex(exacts)
-            exact_val = eval(Symbolics.toexpr(exacts[i]))
-            if isapprox(exact_val, val, atol=1e-6)
-                return exacts[i]
-            elseif isapprox(-exact_val, val, atol=1e-6)
-                return -exacts[i]
-            end
-        end
-    end
+    trig_simplified = check_trig_consts(x)
+    !isequal(trig_simplified, x) && return trig_simplified
 
     if oper === (+)
         args = arguments(x)
@@ -153,3 +135,33 @@ function postprocess_root(x)
     end
     x # unreachable
 end
+
+function check_trig_consts(x)
+    !iscall(x) && return x
+
+    oper = operation(x)
+    inv_opers = [asin, acos, atan]
+    inv_exacts = [0, Symbolics.term(*, pi),
+        Symbolics.term(/,pi,3),
+        Symbolics.term(/, pi, 2),
+        Symbolics.term(/, Symbolics.term(*, 2, pi), 3),
+        Symbolics.term(/, pi, 6),
+        Symbolics.term(/, Symbolics.term(*, 5, pi), 6),
+        Symbolics.term(/, pi, 4)
+    ]
+
+    if any(isequal(oper, o) for o in inv_opers) && isempty(Symbolics.get_variables(x))
+        val = eval(Symbolics.toexpr(x))
+        for i in eachindex(inv_exacts)
+            exact_val = eval(Symbolics.toexpr(inv_exacts[i]))
+            if isapprox(exact_val, val, atol=1e-6)
+                return inv_exacts[i]
+            elseif isapprox(-exact_val, val, atol=1e-6)
+                return -inv_exacts[i]
+            end
+        end
+    end
+
+    # add [sin, cos, tan] simplifications in the future?
+    return x
+end