From fba8aad95dc59f2c612a9b31e36fe75e020de17e Mon Sep 17 00:00:00 2001
From: marioalexis <mario.passaglia@gmail.com>
Date: Mon, 9 Dec 2024 17:19:27 -0300
Subject: [PATCH] Fem: Make it possible to run CalculiX with one core - fixes
 #18339

---
 src/Mod/Fem/Gui/DlgSettingsFemCcx.ui              | 8 ++++----
 src/Mod/Fem/femtaskpanels/task_solver_ccxtools.py | 8 +++-----
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/Mod/Fem/Gui/DlgSettingsFemCcx.ui b/src/Mod/Fem/Gui/DlgSettingsFemCcx.ui
index 66084fab86..9289ba959a 100644
--- a/src/Mod/Fem/Gui/DlgSettingsFemCcx.ui
+++ b/src/Mod/Fem/Gui/DlgSettingsFemCcx.ui
@@ -300,11 +300,11 @@
           <property name="alignment">
            <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
           </property>
-          <property name="minimum">
-           <number>1</number>
+          <property name="toolTip">
+           <string>Set to zero to automatically use maximum number of available cores</string>
           </property>
-          <property name="maximum">
-           <number>40</number>
+          <property name="minimum">
+           <number>0</number>
           </property>
           <property name="prefEntry" stdset="0">
            <cstring>AnalysisNumCPUs</cstring>
diff --git a/src/Mod/Fem/femtaskpanels/task_solver_ccxtools.py b/src/Mod/Fem/femtaskpanels/task_solver_ccxtools.py
index 114289aad1..55162bdb05 100644
--- a/src/Mod/Fem/femtaskpanels/task_solver_ccxtools.py
+++ b/src/Mod/Fem/femtaskpanels/task_solver_ccxtools.py
@@ -381,13 +381,11 @@ class _TaskPanel:
             # Set up for multi-threading. Note: same functionality as ccx_tools.py/start_ccx()
             ccx_prefs = FreeCAD.ParamGet(self.PREFS_PATH)
             env = QtCore.QProcessEnvironment.systemEnvironment()
-            num_cpu_pref = ccx_prefs.GetInt("AnalysisNumCPUs", 1)
-            if num_cpu_pref > 1:
+            num_cpu_pref = ccx_prefs.GetInt("AnalysisNumCPUs", 0)
+            if num_cpu_pref >= 1:
                 env.insert("OMP_NUM_THREADS", str(num_cpu_pref))
             else:
-                cpu_count = os.cpu_count()
-                if cpu_count is not None and cpu_count > 1:
-                    env.insert("OMP_NUM_THREADS", str(cpu_count))
+                env.insert("OMP_NUM_THREADS", str(QtCore.QThread.idealThreadCount()))
             self.Calculix.setProcessEnvironment(env)
 
             self.cwd = QtCore.QDir.currentPath()