source file of the GNU LilyPond music typesetter
- (c) 2005--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+ (c) 2005--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
*/
#include <cstdio>
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, inverse_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)
Real ideal = scm_to_double (scm_caar (s));
Real inv_hooke = scm_to_double (scm_cadar (s));
- spacer.add_spring (ideal, inv_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))