fix error message

[lilypond.git] / lily / optimal-page-breaking.cc

diff --git a/lily/optimal-page-breaking.cc b/lily/optimal-page-breaking.cc
index 03d72629a01ea7c080345614e2a44cb5a09440cf..d18ad2837e92ffe2104f0a4ae326bea06b0cc38e 100644 (file)
--- a/lily/optimal-page-breaking.cc
+++ b/lily/optimal-page-breaking.cc
@@ -5,7 +5,7 @@
 
   source file of the GNU LilyPond music typesetter
 
-  (c) 2006 Joe Neeman <joeneeman@gmail.com>
+  (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
 */
 
 #include "optimal-page-breaking.hh"
@@ -50,21 +50,23 @@ Optimal_page_breaking::try_page_spacing (Line_division const &line_count)
   /* add in the line penalties */
   Real line_force = 0;
   Real line_penalty = 0;
-  Real page_weighting = robust_scm2double (book_->paper_->c_variable ("page-spacing-weight"), 1);
+  Real page_weighting = robust_scm2double (book_->paper_->c_variable ("page-spacing-weight"), 10);
 
   for (vsize i = 0; i < lines.size (); i++)
     {
-      line_force += fabs (lines[i].force_);
+      line_force += lines[i].force_ * lines[i].force_;
       line_penalty += lines[i].break_penalty_;
     }
 
   ret.demerits_ = ret.force_[0] * ret.force_[0] * page_weighting;
   for (vsize i = 1; i < ret.force_.size (); i++)
-    {
-      Real uniformity = fabs (ret.force_[i] - ret.force_[i-1]);
-      ret.demerits_ += (ret.force_[i] * ret.force_[i]
-                      + uniformity * uniformity) * page_weighting;
-    }
+    ret.demerits_ += ret.force_[i] * ret.force_[i] * page_weighting;
+
+  /* for a while we tried averaging page and line forces instead of summing
+     them, but it caused the following problem. If there is a single page
+     with a very bad page force (for example because of a forced page break),
+     the page breaker will put in a _lot_ of pages so that the bad force
+     becomes averaged out over many pages. */
   ret.demerits_ += line_force + line_penalty;
   return ret;
 }