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move recomputation of n_infs in parallel cols #41

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Merged
dance858 merged 1 commit into from
Feb 23, 2026
Merged

move recomputation of n_infs in parallel cols #41

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53 changes: 34 additions & 19 deletions src/explorers/Parallel_cols.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@
#include "Workspace.h"

static inline PresolveStatus process_single_bin(const Problem *prob, const int *bin,
int bin_size)
int bin_size, int *rows_to_recompute)
{
assert(bin_size > 1);
Constraints *constraints = prob->constraints;
Expand All @@ -42,7 +42,6 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
const Matrix *AT = constraints->AT;
const RowRange *col_ranges = AT->p;
const double *c = prob->obj->c;
Activity *acts = constraints->state->activities;
iVec *sub_cols_to_delete = constraints->state->sub_cols_to_delete;
PostsolveInfo *postsolve_info = constraints->state->postsolve_info;

Expand Down Expand Up @@ -157,7 +156,7 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
}

// ---------------------------------------------------------------------
// mark col as substituted
// mark col k as substituted
// ---------------------------------------------------------------------
set_col_to_substituted(k, col_tags + k, sub_cols_to_delete);
save_retrieval_parallel_col(postsolve_info, ub_j_old, lb_j_old,
Expand Down Expand Up @@ -241,11 +240,12 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
return UNBNDORINFEAS;
}

assert(!HAS_TAG(col_tags[k], C_TAG_INACTIVE));
assert(!HAS_TAG(col_tags[j], C_TAG_INACTIVE));
assert(!IS_ABS_INF(bounds[j].lb));
fix_col(constraints, j, bounds[j].lb, cj);
// break from checking if xj is parallel to other cols since
// we fix it
recount_ninfs = false;
// break from checking if xj is parallel to other cols since
// we fix it
break;
}
else if (fix_xj_to_upper)
Expand All @@ -255,11 +255,12 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
return UNBNDORINFEAS;
}

assert(!HAS_TAG(col_tags[k], C_TAG_INACTIVE));
assert(!HAS_TAG(col_tags[j], C_TAG_INACTIVE));
assert(!IS_ABS_INF(bounds[j].ub));
fix_col(constraints, j, bounds[j].ub, cj);
// break from checking if xj is parallel to other cols since
// we fix it
recount_ninfs = false;
// break from checking if xj is parallel to other cols since
// we fix it
break;
}
}
Expand All @@ -269,15 +270,9 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
// j appears in due to bound change
if (recount_ninfs)
{
const Matrix *A = constraints->A;

for (jj = 0; jj < len_j; jj++)
{
int row = aj_cols[jj];

recompute_n_infs(acts + row, A->x + A->p[row].start,
A->i + A->p[row].start,
A->p[row].end - A->p[row].start, col_tags);
rows_to_recompute[aj_cols[jj]] = 1;
}
}
}
Expand All @@ -286,21 +281,39 @@ static inline PresolveStatus process_single_bin(const Problem *prob, const int *
}

static PresolveStatus process_all_bins(const Problem *prob, const int *parallel_cols,
const iVec *groups)
const iVec *groups, int *rows_to_recompute)
{
if (groups->len <= 1)
{
return UNCHANGED;
}

Constraints *constraints = prob->constraints;
size_t n_rows = constraints->A->m;
memset(rows_to_recompute, 0, n_rows * sizeof(int));

size_t n_groups = groups->len - 1;
PresolveStatus status = UNCHANGED;

for (size_t i = 0; i < n_groups; ++i)
{
int n_cols_this_group = groups->data[i + 1] - groups->data[i];
status |= process_single_bin(prob, parallel_cols + groups->data[i],
n_cols_this_group);
n_cols_this_group, rows_to_recompute);
}

// batch recompute n_infs for all affected rows
const Matrix *A = constraints->A;
Activity *acts = constraints->state->activities;
ColTag *col_tags = constraints->col_tags;

for (size_t i = 0; i < n_rows; ++i)
{
if (rows_to_recompute[i])
{
recompute_n_infs(acts + i, A->x + A->p[i].start, A->i + A->p[i].start,
A->p[i].end - A->p[i].start, col_tags);
}
}

return status;
Expand Down Expand Up @@ -337,7 +350,9 @@ PresolveStatus remove_parallel_cols(Problem *prob)
}
#endif

PresolveStatus status = process_all_bins(prob, parallel_cols, group_starts);
int *rows_to_recompute = sparsity_IDs;
PresolveStatus status =
process_all_bins(prob, parallel_cols, group_starts, rows_to_recompute);
assert(constraints->state->empty_rows->len == 0);

delete_fixed_cols_from_problem(prob);
Expand Down