Sketcher: Solver Advanced Control: New Param: QR Pivot Threshold

================================================================

A new parameter added to the form in order to control how low a value should be
to be considered zero (how high a value shall be to be accounted for in rank calculation)

Debug for QR pivot threshold is also added.

src/Mod/Sketcher/App/Sketch.h

@@ -386,6 +386,7 @@ public:
     inline void setConvergence(double conv){GCSsys.convergence=conv;}
     inline void setConvergenceRedundant(double conv){GCSsys.convergenceRedundant=conv;}
     inline void setQRAlgorithm(GCS::QRAlgorithm alg){GCSsys.qrAlgorithm=alg;}
+    inline void setQRPivotThreshold(double val){GCSsys.qrpivotThreshold=val;}
     inline void setLM_eps(double val){GCSsys.LM_eps=val;}
     inline void setLM_eps1(double val){GCSsys.LM_eps1=val;}
     inline void setLM_tau(double val){GCSsys.LM_tau=val;}

src/Mod/Sketcher/App/planegcs/GCS.cpp

@@ -166,7 +166,8 @@ System::System()
   LM_eps(1E-10), LM_eps1(1E-80), LM_tau(1E-3),
   DL_tolg(1E-80), DL_tolx(1E-80), DL_tolf(1E-10),
   LM_epsRedundant(1E-10), LM_eps1Redundant(1E-80), LM_tauRedundant(1E-3),
-  DL_tolgRedundant(1E-80), DL_tolxRedundant(1E-80), DL_tolfRedundant(1E-10)
+  DL_tolgRedundant(1E-80), DL_tolxRedundant(1E-80), DL_tolfRedundant(1E-10),
+  qrpivotThreshold(1E-13)
 {
     // currently Eigen only supports multithreading for multiplications
     // There is no appreciable gain from using more threads
@@ -1818,7 +1819,7 @@ int System::diagnose(Algorithm alg)
             
             paramsNum = qrJT.rows();
             constrNum = qrJT.cols();
-            qrJT.setThreshold(1e-13);
+            qrJT.setThreshold(qrpivotThreshold);
             rank = qrJT.rank();
 
             if (constrNum >= paramsNum)
@@ -1839,7 +1840,7 @@ int System::diagnose(Algorithm alg)
             
             paramsNum = SqrJT.rows();
             constrNum = SqrJT.cols();
-            SqrJT.setPivotThreshold(1e-13);
+            SqrJT.setPivotThreshold(qrpivotThreshold);
             rank = SqrJT.rank();
             
             if (constrNum >= paramsNum)
@@ -1858,7 +1859,8 @@ int System::diagnose(Algorithm alg)
             stream  << ", Threads: " << Eigen::nbThreads()
                     #ifdef EIGEN_VECTORIZE
                     << ", Vectorization: On"
-                    #endif                
+                    #endif            
+                    << ", Pivot Threshold: " << qrpivotThreshold                    
                     << ", Params: " << paramsNum
                     << ", Constr: " << constrNum
                     << ", Rank: "   << rank         << "\n";

src/Mod/Sketcher/App/planegcs/GCS.h

@@ -103,6 +103,7 @@ namespace GCS
         double convergence;
         double convergenceRedundant;
         QRAlgorithm qrAlgorithm;
+        double qrpivotThreshold;
         DebugMode debugMode;
         double LM_eps;
         double LM_eps1;