From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Thu, 16 Jan 2020 21:22:34 +0000 (-0700)
Subject: Increase the precision of the output.
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c7db8f5a4a28d1ac51f3518c9d28856c8cb5c62;p=code-gallery.git

Increase the precision of the output.
---

diff --git a/MCMC-Laplace/mcmc-laplace.cc b/MCMC-Laplace/mcmc-laplace.cc
index 483ea24..a390ceb 100644
--- a/MCMC-Laplace/mcmc-laplace.cc
+++ b/MCMC-Laplace/mcmc-laplace.cc
@@ -586,6 +586,13 @@ namespace ProposalGenerator
 // formula for accepting a sample slightly more awkward, but if you
 // take exponentials on both sides of the comparison, the formula
 // should become obvious again.
+//
+// Finally, we note that the output is generated with 7 digits of
+// accuracy. (The C++ default is 6 digits.) We do this because,
+// as shown in the paper, we can determine the mean value of the
+// probability distribution we are sampling here to at least six
+// digits of accuracy, and do not want to be limited by the precision
+// of the output.
 namespace Sampler
 {
   class MetropolisHastings
@@ -634,6 +641,8 @@ namespace Sampler
     , accepted_sample_number(0)
   {
     output_file.open("samples-" + dataset_name + ".txt");
+    output_file.precision(7);
+
     random_number_generator.seed(random_seed);
   }