From ad414a1878634c82a773ec6a9f95a29f2914b625 Mon Sep 17 00:00:00 2001
From: marioalexis <mario.passaglia@gmail.com>
Date: Thu, 19 Dec 2024 14:36:12 -0300
Subject: [PATCH] Fem: Add preference entry to set Gmsh number of threads

---
 src/Mod/Fem/Gui/DlgSettingsFemGmsh.ui     | 31 +++++++++++++++++++++++
 src/Mod/Fem/Gui/DlgSettingsFemGmshImp.cpp |  7 +++++
 src/Mod/Fem/femmesh/gmshtools.py          | 13 +++++-----
 3 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/src/Mod/Fem/Gui/DlgSettingsFemGmsh.ui b/src/Mod/Fem/Gui/DlgSettingsFemGmsh.ui
index e6981dc9f2..eceddf9a99 100644
--- a/src/Mod/Fem/Gui/DlgSettingsFemGmsh.ui
+++ b/src/Mod/Fem/Gui/DlgSettingsFemGmsh.ui
@@ -151,6 +151,32 @@
           </property>
          </widget>
         </item>
+        <item row="1" column="0">
+         <widget class="QLabel" name="lbl_threads">
+          <property name="text">
+           <string>Number of threads</string>
+          </property>
+         </widget>
+        </item>
+        <item row="1" column="1">
+         <widget class="Gui::PrefSpinBox" name="sb_threads">
+          <property name="alignment">
+           <set>Qt::AlignLeft|Qt::AlignTrailing|Qt::AlignVCenter</set>
+          </property>
+          <property name="toolTip">
+           <string>Number of threads used for meshing</string>
+          </property>
+          <property name="minimum">
+           <number>1</number>
+          </property>
+          <property name="prefEntry" stdset="0">
+           <cstring>NumOfThreads</cstring>
+          </property>
+          <property name="prefPath" stdset="0">
+           <cstring>Mod/Fem/Gmsh</cstring>
+          </property>
+         </widget>
+        </item>
        </layout>
       </item>
      </layout>
@@ -193,6 +219,11 @@
    <extends>QComboBox</extends>
    <header>Gui/PrefWidgets.h</header>
   </customwidget>
+  <customwidget>
+   <class>Gui::PrefSpinBox</class>
+   <extends>QSpinBox</extends>
+   <header>Gui/PrefWidgets.h</header>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="Resources/Fem.qrc"/>
diff --git a/src/Mod/Fem/Gui/DlgSettingsFemGmshImp.cpp b/src/Mod/Fem/Gui/DlgSettingsFemGmshImp.cpp
index 3c0f8b6d91..c5b789f117 100644
--- a/src/Mod/Fem/Gui/DlgSettingsFemGmshImp.cpp
+++ b/src/Mod/Fem/Gui/DlgSettingsFemGmshImp.cpp
@@ -25,6 +25,7 @@
 #include "PreCompiled.h"
 #ifndef _PreComp_
 #include <QMessageBox>
+#include <QThread>
 #endif
 
 #include <App/Application.h>
@@ -53,6 +54,7 @@ void DlgSettingsFemGmshImp::saveSettings()
     ui->cb_gmsh_binary_std->onSave();
     ui->fc_gmsh_binary_path->onSave();
     ui->cb_log_verbosity->onSave();
+    ui->sb_threads->onSave();
 }
 
 void DlgSettingsFemGmshImp::loadSettings()
@@ -60,6 +62,11 @@ void DlgSettingsFemGmshImp::loadSettings()
     ui->cb_gmsh_binary_std->onRestore();
     ui->fc_gmsh_binary_path->onRestore();
 
+    ParameterGrp::handle hGrp = App::GetApplication().GetParameterGroupByPath(
+        "User parameter:BaseApp/Preferences/Mod/Fem/Gmsh");
+    // determine number of CPU threads
+    ui->sb_threads->setValue(hGrp->GetInt("NumOfThreads", QThread::idealThreadCount()));
+
     populateLogVerbosity();
     ui->cb_log_verbosity->onRestore();
 }
diff --git a/src/Mod/Fem/femmesh/gmshtools.py b/src/Mod/Fem/femmesh/gmshtools.py
index 33093165b2..1ea5a11813 100644
--- a/src/Mod/Fem/femmesh/gmshtools.py
+++ b/src/Mod/Fem/femmesh/gmshtools.py
@@ -30,7 +30,7 @@ __url__ = "https://www.freecad.org"
 import os
 import re
 import subprocess
-from PySide.QtCore import QProcess
+from PySide.QtCore import QProcess, QThread
 
 import FreeCAD
 from FreeCAD import Console
@@ -737,11 +737,12 @@ class GmshTools:
         geo.write("// geo file for meshing with Gmsh meshing software created by FreeCAD\n")
         geo.write("\n")
 
-        cpu_count = os.cpu_count()
-        if cpu_count is not None and cpu_count > 1:
-            geo.write("// enable multi-core processing\n")
-            geo.write(f"General.NumThreads = {cpu_count};\n")
-            geo.write("\n")
+        cpu_count = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Gmsh").GetInt(
+            "NumOfThreads", QThread.idealThreadCount()
+        )
+        geo.write("// enable multi-core processing\n")
+        geo.write(f"General.NumThreads = {cpu_count};\n")
+        geo.write("\n")
 
         geo.write("// open brep geometry\n")
         # explicit use double quotes in geo file