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olena-patches@lrde.epita.fr

October 2009

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4588: Fix behaviour when empty class appears. Fix methods order of the kmean1d loop.
by Yann Jacquelet 01 Oct '09

01 Oct '09

* green/mln/clustering/kmean1d.hh (update_kmean, launch_one_time, is_valid, is_descent_valid): Introduce _is_number_valid which turns to false when empty class appears. * green/mln/clustering/kmean1d.hh (launch_one_time): Fix method call order in kmean's loop. * green/mln/clustering/kmean1d.hh (launch_n_times): Introduce nb_tries that garanties to be infinite loop safe. Update kmean.launch_n_times method call. * green/demo/clustering/kmean1d/kmean1d.cc (do_demo): Add comments. --- trunk/milena/sandbox/ChangeLog | 21 ++++ .../green/demo/clustering/kmean1d/kmean1d.cc | 4 +- .../milena/sandbox/green/mln/clustering/kmean1d.hh | 97 ++++++++++++-------- 3 files changed, 83 insertions(+), 39 deletions(-) diff --git a/trunk/milena/sandbox/ChangeLog b/trunk/milena/sandbox/ChangeLog index 2f6ad31..7f3b3ab 100644 --- a/trunk/milena/sandbox/ChangeLog +++ b/trunk/milena/sandbox/ChangeLog @@ -1,3 +1,24 @@ +2009-09-29 Yann Jacquelet <jacquelet(a)lrde.epita.fr> + + Fix behaviour when empty class appears. Fix methods order of the + kmean1d loop. + + * green/mln/clustering/kmean1d.hh + (update_kmean, launch_one_time, is_valid, is_descent_valid): Introduce + _is_number_valid which turns to false when empty class appears. + + * green/mln/clustering/kmean1d.hh + (launch_one_time): Fix method call order in kmean's loop. + + * green/mln/clustering/kmean1d.hh + (launch_n_times): Introduce nb_tries that garanties to be infinite + loop safe. + + Update kmean.launch_n_times method call. + + * green/demo/clustering/kmean1d/kmean1d.cc + (do_demo): Add comments. + 2009-09-29 Fabien Freling <fabien.freling(a)lrde.epita.fr> Update benchmark for types of image. diff --git a/trunk/milena/sandbox/green/demo/clustering/kmean1d/kmean1d.cc b/trunk/milena/sandbox/green/demo/clustering/kmean1d/kmean1d.cc index f13f783..c0b9944 100644 --- a/trunk/milena/sandbox/green/demo/clustering/kmean1d/kmean1d.cc +++ b/trunk/milena/sandbox/green/demo/clustering/kmean1d/kmean1d.cc @@ -42,7 +42,9 @@ void do_demo(const std::string& image, //mln::trace::quiet = false; kmean.launch_n_times(); - + + // Not safe because we don't test kmean.is_valid() + t_kmean::t_color_dbg color_img = kmean.get_color_dbg(); t_kmean::t_mean_dbg mean_img = kmean.get_mean_dbg(); t_kmean::t_label_dbg label_img = kmean.get_label_dbg(); diff --git a/trunk/milena/sandbox/green/mln/clustering/kmean1d.hh b/trunk/milena/sandbox/green/mln/clustering/kmean1d.hh index 9a8c1ea..9f467bd 100644 --- a/trunk/milena/sandbox/green/mln/clustering/kmean1d.hh +++ b/trunk/milena/sandbox/green/mln/clustering/kmean1d.hh @@ -125,6 +125,7 @@ namespace mln /// \brief Constructor /// \param[in] point : the image as the population of pixels. + /// \param[in] k_center : the number of centers. /// \param[in] watch_dog : the limit to observe the convergence (10). /// \param[in] n_times : the number of times that we executed it (10). @@ -228,6 +229,7 @@ namespace mln //------------------------------------------------------------------------ bool is_valid(); + bool is_number_valid(); bool is_descent_valid(); //------------------------------------------------------------------------ @@ -287,6 +289,9 @@ namespace mln t_result _within_variance; unsigned _current_step; unsigned _current_launching; + bool _is_number_valid; + + static const unsigned _N_TRIES = 3; /// \} @@ -384,8 +389,6 @@ namespace mln // Constructor //-------------------------------------------------------------------------- - /// FIXME k must be a parameter, not a static compilation paramater. - template <typename T, unsigned n> inline kmean1d<T,n>::kmean1d(const t_point_img& point, @@ -396,12 +399,15 @@ namespace mln trace::entering("mln::clustering::kmean1d::kmean1d"); mln_precondition(point.is_valid()); - _k_center = k_center; - _watch_dog = watch_dog; - _n_times = n_times; + _k_center = k_center; + _watch_dog = watch_dog; + _n_times = n_times; - _point = point; - _histo = data::compute(accu::meta::stat::histo1d(), _point); + _point = point; + _histo = data::compute(accu::meta::stat::histo1d(), _point); + + // Results aren't valid since they aren't available + _is_number_valid = false; _number.init_(box1d(point1d(0),point1d(_k_center-1))); _mean.init_(box1d(point1d(0),point1d(_k_center-1))); @@ -804,7 +810,17 @@ namespace mln */ for_all(l) { + // State the stopping propagation Nan flag + _is_number_valid = (0 != _number(l)); + + // Emergency exit + if (!_is_number_valid) + break; + + // Compute the mean _mean(l) /= _number(l); + + // Debugging std::cout << "c" << l << " = " << _mean(l) << std::endl; } @@ -932,45 +948,29 @@ namespace mln bool kmean1d<T,n>::is_descent_valid() { trace::entering("mln::clustering::kmean1d::is_descent_valid"); - bool result = true; - mln_piter(t_number_img) l(_number.domain()); - - for_all(l) - { - result = result && (_number(l) != 0.0); - } - - result = result && (_current_step < _watch_dog); + bool result = _is_number_valid && (_current_step < _watch_dog); trace::exiting("mln::clustering::kmean1d::is_descent_valid"); return result; } - + template <typename T, unsigned n> inline - bool kmean1d<T,n>::is_valid() + bool kmean1d<T,n>::is_number_valid() { trace::entering("mln::clustering::kmean1d::is_valid"); - bool result = true; - mln_piter(t_number_img) l(_number.domain()); - - for_all(l) - { - result = result && (_number(l) != 0.0); - } + bool result = _is_number_valid; trace::exiting("mln::clustering::kmean1d::is_valid"); return result; } - //-------------------------------------------------------------------------- // Main loop //-------------------------------------------------------------------------- - template <typename T, unsigned n> inline void kmean1d<T,n>::launch_one_time() @@ -981,33 +981,40 @@ namespace mln // Initialization to start the descent t_result old_variance = mln_max(t_result); + _within_variance = mln_max(t_result); + _current_step = 0; - // Choose random points and compute within variance + // Build the first group and evaluate its caharacteristics init_mean(); update_distance(); - update_group(); - update_variance(); // update _within_variance - std::cout << "first_variance : " << _within_variance << std::endl; + std::cout << "first_variance : " << old_variance << std::endl; // Execute the descent - for (_current_step = 0; - _current_step < _watch_dog && _within_variance < old_variance; - ++_current_step) + do { old_variance = _within_variance; - update_mean(); - update_distance(); update_group(); + update_mean(); // update _is_number_valid + + // Stopping Nan propagation + if (!_is_number_valid) + break; + + update_distance(); update_variance(); // update _within_variance - // debugging code + + // Debugging code update_cnv(); std::cout << "_current_step : " << _current_step << std::endl; std::cout << "_within_variance : " << _within_variance << std::endl; + + ++_current_step; } + while (_current_step < _watch_dog && _within_variance < old_variance); std::cout << "----------------------------------------" << std::endl; @@ -1016,6 +1023,9 @@ namespace mln trace::exiting("mln::clustering::kmean1d::launch_one_time"); } + /// FIXME There is a risk of infinite loop if convergence is not observed + /// FIXME What do we prefer, bad results or infinite loop ? + template <typename T, unsigned n> inline void kmean1d<T,n>::launch_n_times() @@ -1025,6 +1035,9 @@ namespace mln std::cout << "watch_dog : " << _watch_dog << std::endl; std::cout << "n_times : " << _n_times << std::endl; + // number of times we reexecute launch_one_time without any success + unsigned tries = 0; + _variance_min = mln_max(t_result); _current_launching = 0; @@ -1033,7 +1046,7 @@ namespace mln { launch_one_time(); - if (is_descent_valid()) + if (is_descent_valid() || _N_TRIES < tries) { if (_within_variance < _variance_min) { @@ -1042,6 +1055,9 @@ namespace mln _launching_min = _current_launching; } + // Reinitialize the number of echecs possible + tries = 0; + std::cout << "_current_launching : " << _current_launching << std::endl; @@ -1050,8 +1066,13 @@ namespace mln ++_current_launching; } + else + ++tries; } + //Debugging code + build_all_dbg(); + trace::exiting("mln::clustering::kmean1d::launch_n_times"); } -- 1.5.6.5

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