X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fleast-squares.cc;h=582e5b0dcb2bb655832512338f0fe57489f77cd8;hb=97a0ec882833f3f5247e66027cba28bce0abe471;hp=737cbd6d58743ffc83326504e9c490e9a2a3bc9e;hpb=bb36bac02a64770871780231ecc709cb18b20932;p=lilypond.git

diff --git a/lily/least-squares.cc b/lily/least-squares.cc
index 737cbd6d58..582e5b0dcb 100644
--- a/lily/least-squares.cc
+++ b/lily/least-squares.cc
@@ -1,43 +1,52 @@
-/*   
-  least-squares.cc --  implement minimise_least_squares
-  
+/*
+  least-squares.cc -- implement minimise_least_squares
+
   source file of the GNU LilyPond music typesetter
-  
-  (c) 1996--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
-  
- */
+
+  (c) 1996--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+*/
 
 #include "least-squares.hh"
-#include "warn.hh"
 
+#include "warn.hh"
 
 void
-minimise_least_squares (Real * coef, Real * offset,
-			Array<Offset> input)
+minimise_least_squares (Real *coef, Real *offset,
+			vector<Offset> const &input)
 {
   Real sx = 0.0;
   Real sy = 0.0;
-  Real sqx =0.0;
+  Real sqx = 0.0;
   Real sxy = 0.0;
 
-  for (int i=0; i < input.size();i++) 
+  for (vsize i = 0; i < input.size ();i++)
     {
-      Real x=input[i][X_AXIS];
+      Real x = input[i][X_AXIS];
       Real y = input[i][Y_AXIS];
       sx += x;
       sy += y;
       sqx += sqr (x);
       sxy += x*y;
     }
-  int N = input.size();
 
-  *coef =0.0;
-  *offset =0.;
-  
-  Real den = (N*sqx - sqr (sx));
-  if (!N || !den)
-    programming_error ("minimise_least_squares():  Nothing to minimise");
+  int count = input.size ();
+
+  *coef = 0.0;
+  *offset = 0.;
 
-  *coef = (N * sxy - sx*sy)/den;
-  *offset = (sy - (*coef) * sx)/N;
+  Real den = (count * sqx - sqr (sx));
+  if (!count || !den)
+    {
+      programming_error ("minimise_least_squares ():  Nothing to minimise\n"
+			 "This means that vertical spacing is triggered\n"
+			 "before line breaking\n");
+      *coef = 0.0;
+      *offset = count ? sy / count : 0.0;
+    }
+  else
+    {
+      *coef = (count * sxy - sx * sy) / den;
+      *offset = (sy - (*coef) * sx) / count;
+    }
 }
+