Module: ppl/ppl Branch: sparse_matrices Commit: ebb0a33723717260c322a2e1894931707ce94c43 URL: http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=ebb0a33723717...

Author: Marco Poletti poletti.marco@gmail.com Date: Mon Mar 22 13:02:10 2010 +0100

MIP_Problem: optimize find_create() calls in linear_combine().

---

src/MIP_Problem.cc | 34 ++++++++++++++++++---------------- 1 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/MIP_Problem.cc b/src/MIP_Problem.cc index db51352..95ef74a 100644 --- a/src/MIP_Problem.cc +++ b/src/MIP_Problem.cc @@ -1202,8 +1202,14 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x, if (j->first < i->first) { if (j->first != k) { // FIXME: check if adding "if (j->second != 0)" speeds this up. - last_i = x.find_create(j->first); + + // The following statements are equivalent to + // sub_mul_assign(x[j->first], j->second, normalized_x_k); + last_i = x.find_create(*j); Coefficient& x_i = (*last_i).second; + x_i *= normalized_x_k; + neg_assign(x_i); + #ifdef PPL_SPARSE_BACKEND_INVALIDATES_REFERENCES i = last_i; ++i; @@ -1212,11 +1218,6 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x, // Here we had (j->first < i->first) therefore (&x != &y) . PPL_ASSERT(& static_cast<matrix_row_const_reference_type>(x) != &y); #endif - PPL_ASSERT(x_i == 0); - // sub_mul_assign(x_i, j->second, normalized_x_k); - x_i = j->second; - x_i *= normalized_x_k; - neg_assign(x_i);

++j; break; @@ -1245,8 +1246,14 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x, if (j->first < i->first) { if (j->first != k) { // FIXME: check if adding "if (j->second != 0)" speeds this up. - last_i = x.find_create(j->first, Coefficient_zero(), last_i); + + // The following statements are equivalent to + // sub_mul_assign(x[j->first], j->second, normalized_x_k); + last_i = x.find_create(*j, last_i); Coefficient& x_i = (*last_i).second; + x_i *= normalized_x_k; + neg_assign(x_i); + #ifdef PPL_SPARSE_BACKEND_INVALIDATES_REFERENCES i = last_i; ++i; @@ -1255,11 +1262,6 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x, // Here we had (j->first < i->first) therefore (&x != &y) . PPL_ASSERT(& static_cast<matrix_row_const_reference_type>(x) != &y); #endif - PPL_ASSERT(x_i == 0); - // sub_mul_assign(x_i, j->second, normalized_x_k); - x_i = j->second; - x_i *= normalized_x_k; - neg_assign(x_i); } ++j; } else { @@ -1285,11 +1287,11 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x, while (j != j_end) { if (j->first != k) { // FIXME: check if adding "if (j->second != 0)" speeds this up. - last_i = x.find_create(j->first, Coefficient_zero(), last_i); + + // The following statements are equivalent to + // sub_mul_assign(x[j->first], j->second, normalized_x_k); + last_i = x.find_create(*j, last_i); Coefficient& x_i = (*last_i).second; - PPL_ASSERT(x_i == 0); - // sub_mul_assign(x_i, j->second, normalized_x_k); - x_i = j->second; x_i *= normalized_x_k; neg_assign(x_i); }