Linearization from console executable and xml script

scripts/737_cruise_steady_turn_linearize.xml

@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="utf-8"?>
+<?xml-stylesheet type="text/xsl" href="http://jsbsim.sf.net/JSBSimScript.xsl"?>
+<runscript xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="http://jsbsim.sf.net/JSBSimScript.xsd"
+    name="Cruise flight with steady turn in 737.">
+
+  <description>
+    This is a very simple script that trims the aircraft with running
+    engines, exports linearized equations, and runs out to 10 seconds.
+  </description>
+
+  <use aircraft="737" initialize="cruise_steady_turn_init"/> 
+
+  <run start="0" end="10" dt="0.008333">
+
+    <property value="0"> simulation/notify-time-trigger </property>
+
+    <event name="Set engines running">
+      <condition> simulation/sim-time-sec le 0.1 </condition>
+      <set name="propulsion/engine[0]/set-running" value="1"/>
+      <set name="propulsion/engine[1]/set-running" value="1"/>
+      <notify/>
+    </event>
+
+    <!--
+      For "do_simple_trim" (Classic trim):
+      0: Longitudinal
+      1: Full
+      2: Ground
+      3: Pullup
+      4: Custom
+      5: Turn
+      6: None
+    -->
+
+    <event name="Trim and linearize">
+      <condition>
+        simulation/sim-time-sec gt 0.1
+      </condition>
+      <set name="simulation/do_simple_trim" value="5"/>
+      <set name="simulation/do_linearization" value="0"/>
+    </event>
+
+    <event name="Repeating Notify" persistent="true">
+      <description>Output message at 5 second intervals</description>
+      <notify>
+        <property>propulsion/engine[0]/n2</property>
+        <property>propulsion/engine[1]/n2</property>
+        <property>propulsion/engine[0]/thrust-lbs</property>
+        <property>propulsion/engine[1]/thrust-lbs</property>
+        <property>position/h-agl-ft</property>
+        <property>velocities/vc-kts</property>
+        <property>velocities/vc-fps</property>
+        <property>velocities/vt-fps</property>
+        <property>attitude/phi-rad</property>
+        <property>attitude/theta-rad</property>
+        <property>attitude/psi-rad</property>
+      </notify>
+      <condition> simulation/sim-time-sec >= simulation/notify-time-trigger </condition>
+      <set name="simulation/notify-time-trigger" value="5" type="FG_DELTA"/>
+    </event>
+
+  </run>
+
+</runscript>

src/FGFDMExec.cpp

@@ -60,6 +60,7 @@ INCLUDES
 #include "models/FGAuxiliary.h"
 #include "models/FGInput.h"
 #include "initialization/FGTrim.h"
+#include "initialization/FGLinearization.h"
 #include "input_output/FGScript.h"
 #include "input_output/FGXMLFileRead.h"
 #include "initialization/FGInitialCondition.h"
@@ -158,6 +159,7 @@ FGFDMExec::FGFDMExec(FGPropertyManager* root, std::shared_ptr<unsigned int> fdmc
   Constructing = true;
   typedef int (FGFDMExec::*iPMF)(void) const;
   instance->Tie("simulation/do_simple_trim", this, (iPMF)0, &FGFDMExec::DoTrim);
+  instance->Tie("simulation/do_linearization", this, (iPMF)0, &FGFDMExec::DoLinearization);
   instance->Tie("simulation/reset", this, (iPMF)0, &FGFDMExec::ResetToInitialConditions);
   instance->Tie("simulation/disperse", this, &FGFDMExec::GetDisperse);
   instance->Tie("simulation/randomseed", this, (iPMF)&FGFDMExec::SRand, &FGFDMExec::SRand);
@@ -1315,6 +1317,16 @@ void FGFDMExec::DoTrim(int mode)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+void FGFDMExec::DoLinearization(int)
+{
+  double dt0 = this->GetDeltaT();
+  FGLinearization lin(this);
+  lin.WriteScicoslab();
+  this->Setdt(dt0);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
 void FGFDMExec::SRand(int sr)
 {
   RandomSeed = sr;

src/FGFDMExec.h

@@ -475,6 +475,11 @@ class JSBSIM_API FGFDMExec : public FGJSBBase
   * - tNone  */
   void DoTrim(int mode);
 
+  /** Executes linearization with state-space output
+   * You must trim first to get an accurate state-space model
+   */
+  void DoLinearization(int);
+
   /// Disables data logging to all outputs.
   void DisableOutput(void) { Output->Disable(); }
   /// Enables data logging to all outputs.

src/initialization/FGLinearization.cpp

@@ -87,9 +87,10 @@ void FGLinearization::WriteScicoslab() const {
 }
 
 void FGLinearization::WriteScicoslab(std::string& path) const {
-    int width=10;
+    int width=20;
+    int precision=10;
     std::ofstream scicos(path.c_str());
-    scicos.precision(10);
+    scicos.precision(precision);
     width=20;
     scicos  << std::scientific
             << aircraft_name << ".x0=..\n" << std::setw(width) << x0 << ";\n"
@@ -101,6 +102,8 @@ void FGLinearization::WriteScicoslab(std::string& path) const {
             << std::setw(width) << D << ");\n"
             << aircraft_name << ".tfm = ss2tf(" << aircraft_name << ".sys);\n"
             << std::endl;
+    scicos.close();
+
 }
 
 } // JSBSim