Module: ppl/ppl Branch: pip Commit: 2649737035a99c2ebee2e55411f9a4a27eb936fd URL: http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=2649737035a99...

Author: Enea Zaffanella zaffanella@cs.unipr.it Date: Wed Feb 3 08:50:28 2010 +0100

Improved method Tableau::is_better_pivot().

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src/PIP_Tree.cc | 60 ++++++++++++++++++++++++++++++++---------------------- 1 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/src/PIP_Tree.cc b/src/PIP_Tree.cc index 9720f6f..d20b16f 100644 --- a/src/PIP_Tree.cc +++ b/src/PIP_Tree.cc @@ -744,34 +744,44 @@ bool PIP_Solution_Node::Tableau ::is_better_pivot(const std::vector<dimension_type>& mapping, const std::vector<bool>& basis, - const dimension_type i, - const dimension_type j, - const dimension_type i_, - const dimension_type j_) const { - dimension_type k; - dimension_type num_params = t.num_columns(); - dimension_type num_rows = s.num_rows(); - const Row& s_i = s[i]; - const Row& s_i_ = s[i_]; - const Row& t_i = t[i]; - const Row& t_i_ = t[i_]; - bool columns_are_different = false; - for (k=0; k<num_params; ++k) { - PPL_DIRTY_TEMP_COEFFICIENT(t_ikXs_i_j_); - PPL_DIRTY_TEMP_COEFFICIENT(t_i_kXs_ij); - t_ikXs_i_j_ = t_i[k] * s_i_[j_]; - t_i_kXs_ij = t_i_[k] * s_i[j]; - for (dimension_type x=0; x<num_rows; ++x) { - const Row& s_x = s[x]; - if (s_x[j] * t_ikXs_i_j_ != s_x[j_] * t_i_kXs_ij) { - columns_are_different = true; - goto endloop; + const dimension_type row_0, + const dimension_type col_0, + const dimension_type row_1, + const dimension_type col_1) const { + const dimension_type num_params = t.num_columns(); + const dimension_type num_rows = s.num_rows(); + const Row& s_0 = s[row_0]; + const Row& s_1 = s[row_1]; + const Coefficient& s_0_0 = s_0[col_0]; + const Coefficient& s_1_1 = s_1[col_1]; + const Row& t_0 = t[row_0]; + const Row& t_1 = t[row_1]; + PPL_DIRTY_TEMP_COEFFICIENT(coeff_0); + PPL_DIRTY_TEMP_COEFFICIENT(coeff_1); + PPL_DIRTY_TEMP_COEFFICIENT(product_0); + PPL_DIRTY_TEMP_COEFFICIENT(product_1); + // On exit from the loop, if j_mismatch == num_params then + // no column mismatch was found. + dimension_type j_mismatch = num_params; + for (dimension_type j = 0; j < num_params; ++j) { + coeff_0 = t_0[j] * s_1_1; + coeff_1 = t_1[j] * s_0_0; + for (dimension_type i = 0; i < num_rows; ++i) { + const Row& s_i = s[i]; + product_0 = coeff_0 * s_i[col_0]; + product_1 = coeff_1 * s_i[col_1]; + if (product_0 != product_1) { + // Mismatch found: exit from both loops. + j_mismatch = j; + goto end_loop; } } } -endloop: - return columns_are_different - && column_lower(s, mapping, basis, s_i, j, s_i_, j_, t_i[k], t_i_[k]); + + end_loop: + return (j_mismatch != num_params) + && column_lower(s, mapping, basis, s_0, col_0, s_1, col_1, + t_0[j_mismatch], t_1[j_mismatch]); }

void