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simple-spacer-scheme.cc -- implement Simple_spacer
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source file of the GNU LilyPond music typesetter
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(c) 2005--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
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#include "paper-column.hh"
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#include "simple-spacer.hh"
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LY_DEFINE (ly_solve_spring_rod_problem, "ly:solve-spring-rod-problem",
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4, 1, 0, (SCM springs, SCM rods, SCM length, SCM ragged),
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"Solve a spring and rod problem for @var{count} objects, that "
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"are connected by @var{count-1} springs, and an arbitrary number of rods "
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"Springs have the format (ideal, hooke) and rods (idx1, idx2, distance) "
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"@var{length} is a number, @var{ragged} a boolean "
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"Return: a list containing the force (positive for stretching, "
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"negative for compressing and #f for non-satisfied constraints) "
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"followed by the @var{spring-count}+1 positions of the objects. ")
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int len = scm_ilength (springs);
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return scm_list_2 (scm_from_double (0.0), scm_from_double (0.0));
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SCM_ASSERT_TYPE (len >= 0, springs, SCM_ARG1, __FUNCTION__, "list of springs");
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SCM_ASSERT_TYPE (scm_ilength (rods) >= 0, rods, SCM_ARG2, __FUNCTION__, "list of rods");
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SCM_ASSERT_TYPE (scm_is_number (length) || length == SCM_BOOL_F,
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length, SCM_ARG3, __FUNCTION__, "number or #f");
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bool is_ragged = ragged == SCM_BOOL_T;
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for (SCM s = springs; scm_is_pair (s); s = scm_cdr (s))
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Real ideal = scm_to_double (scm_caar (s));
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Real hooke = scm_to_double (scm_cadar (s));
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spacer.add_spring (ideal, 1 / hooke);
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for (SCM s = rods; scm_is_pair (s); s = scm_cdr (s))
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SCM entry = scm_car (s);
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int l = scm_to_int (scm_car (entry));
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int r = scm_to_int (scm_cadr (entry));
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entry = scm_cddr (entry);
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Real distance = scm_to_double (scm_car (entry));
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spacer.add_rod (l, r, distance);
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spacer.line_len_ = scm_to_double (length);
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spacer.my_solve_natural_len ();
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spacer.my_solve_linelen ();
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posns.push_back (0.0);
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for (vsize i = 0; i < spacer.springs_.size (); i++)
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Real l = spacer.springs_[i].length ((is_ragged) ? 0.0 : spacer.force_);
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posns.push_back (posns.back () + l);
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SCM force_return = SCM_BOOL_F;
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if (!isinf (spacer.force_)
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&& (spacer.is_active () || is_ragged))
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force_return = scm_from_double (spacer.force_);
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&& posns.back () > spacer.line_len_)
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force_return = SCM_BOOL_F;
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for (vsize i = posns.size (); i--;)
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retval = scm_cons (scm_from_double (posns[i]), retval);
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retval = scm_cons (force_return, retval);