source file of the GNU LilyPond music typesetter
- (c) 2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
-
+ (c) 2005--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
*/
-
#include <cstdio>
-#include <math.h>
-#include "libc-extension.hh" // isinf
#include "paper-column.hh"
#include "spring.hh"
#include "warn.hh"
#include "simple-spacer.hh"
-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. "
- )
+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. ")
{
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");
-
- bool is_ragged = ragged == SCM_BOOL_T;
- Simple_spacer spacer;
+ 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));
- spacer.add_spring (ideal, hooke);
+ spacer.add_spring (ideal, 1 / hooke);
}
for (SCM s = rods; scm_is_pair (s); s = scm_cdr (s))
int l = scm_to_int (scm_car (entry));
int r = scm_to_int (scm_cadr (entry));
entry = scm_cddr (entry);
-
+
Real distance = scm_to_double (scm_car (entry));
spacer.add_rod (l, r, distance);
}
spacer.line_len_ = scm_to_double (length);
-
+
if (is_ragged)
spacer.my_solve_natural_len ();
else
Array<Real> posns;
posns.push (0.0);
- for (int i = 0; i < spacer.springs_.size(); i++)
+ for (int i = 0; i < spacer.springs_.size (); i++)
{
Real l = spacer.springs_[i].length ((is_ragged) ? 0.0 : spacer.force_);
- posns.push (posns.top() + l);
+ posns.push (posns.top () + l);
}
-
-
SCM force_return = SCM_BOOL_F;
if (!isinf (spacer.force_)
&& (spacer.is_active () || is_ragged))
- {
- force_return = scm_from_double (spacer.force_);
- }
+ force_return = scm_from_double (spacer.force_);
if (is_ragged
&& posns.top () > spacer.line_len_)
- {
- force_return = SCM_BOOL_F;
- }
+ force_return = SCM_BOOL_F;
SCM retval = SCM_EOL;
- for (int i = posns.size(); i--;)
- {
- retval = scm_cons (scm_from_double (posns[i]), retval);
- }
+ for (int i = posns.size (); i--;)
+ retval = scm_cons (scm_from_double (posns[i]), retval);
retval = scm_cons (force_return, retval);
- return retval;
+ return retval;
}