elucidate minimize least_sq error message.

diff --git a/lily/least-squares.cc b/lily/least-squares.cc
index d95279a54e0d801420b28b6348f3b0f76f2583d1..582e5b0dcb2bb655832512338f0fe57489f77cd8 100644 (file)
--- a/lily/least-squares.cc
+++ b/lily/least-squares.cc
@@ -37,7 +37,9 @@ minimise_least_squares (Real *coef, Real *offset,
   Real den = (count * sqx - sqr (sx));
   if (!count || !den)
     {
-      programming_error ("minimise_least_squares ():  Nothing to minimise");
+      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;
     }