increase the cut-back factor to 0.85 for a better time stepping behavior

Author: yangbai90

include/TimeStepping/TimeSteppingBlock.h

@@ -29,7 +29,7 @@ class TimeSteppingBlock{
     PetscReal _dtmax=0.1,_dtmin=1.0e-12,_dt0=1.0e-5;
     PetscInt _interval=1;
     PetscInt _nOpts=4;
-    PetscReal _CutFactor=0.8,_GrowthFactor=1.1;
+    PetscReal _CutFactor=0.85,_GrowthFactor=1.1;
     bool _IsAdaptive=false;
 
     void Reset(){
@@ -39,7 +39,7 @@ class TimeSteppingBlock{
         _dtmax=0.1;
         _dtmin=1.0e-12;
         _dt0=1.0e-5;
-        _CutFactor=0.8;
+        _CutFactor=0.85;
         _GrowthFactor=1.1;
         _interval=1;
         _nOpts=4;

src/TimeStepping/TimeStepping.cpp

@@ -16,6 +16,6 @@ TimeStepping::TimeStepping(){
     _dt0=1.0e-5;
     _interval=1;
     _IsAdaptive=false;
-    _CutFactor=0.8;_GrowthFactor=1.1;
-    _nOpts=5;
+    _CutFactor=0.85;_GrowthFactor=1.1;
+    _nOpts=4;
 }