+ /* strength == INF is possible. It means fixed distance. */
+ programming_error ("insane distance found");
+ distance = 1.0;
+ inverse_strength = 1.0;
+ }
+
+#ifndef NDEBUG
+ SCM mins = me->get_object ("ideal-distances");
+ for (SCM s = mins; scm_is_pair (s); s = scm_cdr (s))
+ {
+ Spring_smob *sp = unsmob_spring (scm_car (s));
+ if (sp->other_ == other)