X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fsimple-spacer-scheme.cc;h=04ceef94f6a5abb79206bc4e661f667509996637;hb=5b4b0d6e9a197e8f9eb085b7c2ad78b8be3e5cfc;hp=24b6d1c76351f3830d105651c75eb46644332ba8;hpb=a276a19dc6bd57832db3107f2f2cbb04cb4677b6;p=lilypond.git

diff --git a/lily/simple-spacer-scheme.cc b/lily/simple-spacer-scheme.cc
index 24b6d1c763..04ceef94f6 100644
--- a/lily/simple-spacer-scheme.cc
+++ b/lily/simple-spacer-scheme.cc
@@ -3,7 +3,7 @@
 
   source file of the GNU LilyPond music typesetter
 
-  (c) 2005--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  (c) 2005--2008 Han-Wen Nienhuys <hanwen@xs4all.nl>
 */
 
 #include <cstdio>
@@ -15,31 +15,40 @@
 
 LY_DEFINE (ly_solve_spring_rod_problem, "ly:solve-spring-rod-problem",
 	   4, 1, 0, (SCM springs, SCM rods, SCM length, SCM ragged),
-	   "Solve a spring and rod problem for @var{count} objects, that "
-	   "are connected by @var{count-1} springs, and an arbitrary number of rods "
-	   "Springs have the format (ideal, hooke) and rods (idx1, idx2, distance) "
-	   "@var{length} is a number, @var{ragged} a boolean "
-	   "Return: a list containing the force (positive for stretching, "
-	   "negative for compressing and #f for non-satisfied constraints) "
-	   "followed by the @var{spring-count}+1 positions of the objects. ")
+	   "Solve a spring and rod problem for @var{count} objects, that"
+	   " are connected by @var{count}-1 @var{springs}, and an arbitrary"
+	   " number of @var{rods}.  @var{count} is implicitly given by"
+	   " @var{springs} and @var{rods}.  The @var{springs} argument has"
+	   " the format @code{(ideal, inverse_hook)} and @var{rods} is of"
+	   " the form @code{(idx1, idx2, distance)}.\n"
+	   "\n"
+	   "@var{length} is a number, @var{ragged} a boolean.\n"
+	   "\n"
+	   "The function returns a list containing the force (positive for"
+	   " stretching, negative for compressing and @code{#f} for"
+	   " non-satisfied constraints) followed by @var{spring-count}+1"
+	   " positions of the objects.")
 {
   int len = scm_ilength (springs);
   if (len == 0)
     return scm_list_2 (scm_from_double (0.0), scm_from_double (0.0));
 
   SCM_ASSERT_TYPE (len >= 0, springs, SCM_ARG1, __FUNCTION__, "list of springs");
-  SCM_ASSERT_TYPE (scm_ilength (rods) >= 0, rods, SCM_ARG2, __FUNCTION__, "list of rods");
-  SCM_ASSERT_TYPE (scm_is_number (length) || length == SCM_BOOL_F,
-		   length, SCM_ARG3, __FUNCTION__, "number or #f");
+  SCM_ASSERT_TYPE (scm_ilength (rods)  > 0, rods, SCM_ARG1, __FUNCTION__, "list of rods");
+  LY_ASSERT_TYPE (scm_is_number, length, 3);
 
   bool is_ragged = ragged == SCM_BOOL_T;
   Simple_spacer spacer;
   for (SCM s = springs; scm_is_pair (s); s = scm_cdr (s))
     {
       Real ideal = scm_to_double (scm_caar (s));
-      Real hooke = scm_to_double (scm_cadar (s));
+      Real inv_hooke = scm_to_double (scm_cadar (s));
 
-      spacer.add_spring (ideal, 1 / hooke);
+      Spring sp (ideal, 0.0);
+      sp.set_inverse_compress_strength (inv_hooke);
+      sp.set_inverse_stretch_strength (inv_hooke);
+
+      spacer.add_spring (sp);
     }
 
   for (SCM s = rods; scm_is_pair (s); s = scm_cdr (s))