From 7cc8daf74068ddac500c08b72a8fe730c5ec29a4 Mon Sep 17 00:00:00 2001
From: Hantao Cui <cuihantao@gmail.com>
Date: Sun, 31 Mar 2024 17:16:54 +0000
Subject: [PATCH] Update.

---
 andes/core/symprocessor.py    | 11 +++++++++--
 docs/source/release-notes.rst |  6 ++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/andes/core/symprocessor.py b/andes/core/symprocessor.py
index 06f1202ea..e0aa4a119 100644
--- a/andes/core/symprocessor.py
+++ b/andes/core/symprocessor.py
@@ -118,11 +118,18 @@ def generate_symbols(self):
                 self.tex_names[name] = sp.Symbol(tex_name)
         # -----------------------------------------------------------
 
+        # `all_params_names` include parameters, services, exports from blocks, etc.
         for var in self.cache.all_params_names:
+            is_real = True
+
+            if var in self.parent.services:
+                if self.parent.services[var].vtype == complex:
+                    is_real = False
+
             self.inputs_dict[var] = sp.Symbol(var)
 
         for var in self.cache.all_vars_names:
-            tmp = sp.Symbol(var)
+            tmp = sp.Symbol(var, real=True)  # all DAE variables are real
             self.vars_dict[var] = tmp
             self.inputs_dict[var] = tmp
             if var in self.cache.vars_int:
@@ -130,7 +137,7 @@ def generate_symbols(self):
 
         # store tex names defined in `self.config`
         for key in self.config.as_dict():
-            tmp = sp.Symbol(key)
+            tmp = sp.Symbol(key, real=True)  # not expecting complex numbers in config
             self.inputs_dict[key] = tmp
             if key in self.config.tex_names:
                 self.tex_names[tmp] = sp.Symbol(self.config.tex_names[key])
diff --git a/docs/source/release-notes.rst b/docs/source/release-notes.rst
index d766892bc..ae131afad 100644
--- a/docs/source/release-notes.rst
+++ b/docs/source/release-notes.rst
@@ -9,6 +9,12 @@ The APIs before v3.0.0 are in beta and may change without prior notice.
 v1.9 Notes
 ==========
 
+v1.9.3 (2024-04-XX)
+-------------------
+- In symbolic processor, most variables are assumed to be real, except some
+  services that are specified as complex. This will allow generating simplified
+  expressions.
+
 v1.9.2 (2024-03-25)
 -------------------
 - Improve PSS/E parser for the `wmod` field in the static generator