put back Marta's parameter for scale

src/camel/MCMC/exec/mainMCMC.cc

@@ -70,7 +70,7 @@ int main(int argc, char *argv[])
   const string proposal_cov=parser.params.find<string>("proposal_cov","");
   const int t0=parser.params.find<int>("t0",2000);
   const int ts=parser.params.find<int>("ts",10000);
-  double scale=parser.params.find<double>("scale",-1);
+  double scale=parser.params.find<double>("scale",0.001);
   const bool do_move=parser.params.find<bool>("do_move",false);
   bool verbose=parser.params.find<bool>("verbose",false);
 
@@ -89,12 +89,6 @@ int main(int argc, char *argv[])
   const int dim=lkh->Get_par_num();
 
   cout <<"dim=" <<dim <<endl;
-
-  //SP 25/06/19: compute scale if undefined depending on dim
-  if (scale<0) {
-      scale=2.38*2.38/dim;
-      cout << "defining scale factor as " << scale << endl;
-  }
   //--------defining seeds-----------------------------------------------
   unsigned int seed(0);
   if (parser.params.param_present("seed")){

work/ref/hlpTT_PS_H0.cml

@@ -71,10 +71,8 @@ class     sBBN\ file            bbn/sBBN_2017_marcucci.dat
 
 precisionFile=class_pre/hpjul3.pre
 ###############################################################
+# minimization
 
-
-###############################################################
-#fitter
 nitermax=50000
 set_stra=2
 set_tol=0.00001
@@ -83,3 +81,14 @@ set_tol=0.00001
 remove_cosmo_limits=false
 doHesse=true
 ###############################################################
+#MCMC
+#1st samples are drawn up to t0 from given proposal (scaled by scale)
+#if your matrix is nice scale_th~2.4**2/ndim otherwise low (default=0.001)
+#t0=2000
+#scale=0.3
+
+#then cov is adapted up to ts with scale_th. If your matrix is nice do
+# not destroy things there.
+#ts=0
+
+#then scale will auto-adapt to reach ar~0.25