Add lp.batch_explain_fixed_in_row (default true) so the batched
linearization of fixed-column bound witnesses in explain_fixed_in_row
can be toggled off, restoring the per-column explanation behavior for
A/B benchmarking.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
## Summary
Improves the Diophantine (`dio`) integer-feasibility controller in
`int_solver`, and fixes a latent bug where the user's Gomory-cut
configuration could be silently overridden at runtime. Also includes the
earlier `lia_w` work: randomized hammer gates, the `int_hammer_period` /
`random_hammers` parameters, and the linear `dio_calls_period` recovery.
## Motivation
The controller used a **single field** both as the static
`lp.dio_cuts_enable_gomory` parameter and as the live "is Gomory
running" flag. It started running Gomory (and the gcd test) once
`dio_calls_period` crossed a hard-coded `16`. Because `dio_calls_period`
is also driven by the randomized hammer gate, on instances where `dio`
is only intermittently productive the period could be ratcheted past 16
*by chance*, turning on Gomory + gcd and thrashing — e.g. `dillig/20-14`
went from a 100s solve (deterministic) to a 600s timeout (randomized)
purely from this spurious activation.
## Changes
- **Separate config from runtime state.** Split the shared field into
`m_dio_cuts_enable_gomory` (static config, never mutated) and
`m_run_gomory_with_dio` (runtime flag). Toggling the runtime state can
no longer clobber the user's `dio_cuts_enable_gomory` parameter.
- **Trigger on genuine dio failures, not the period proxy.** Running
Gomory-with-dio now starts after a count of **consecutive `undef` dio
returns** (reset on a dio conflict) rather than when the
randomization-inflated period crosses a threshold — robust to
`random_hammers` gate variance.
- **Parameterize the threshold.** New `lp.dio_gomory_enable_period`
(default 16). Set it very large to never auto-start Gomory, so Gomory
follows `dio_cuts_enable_gomory` only.
- **Try `dio` before Gomory** in `check()` so a productive dio conflict
preempts Gomory on dio-dominated instances.
## Evaluation (QF_LIA, full set, 600s, seed 555 paired)
- Dio-before-Gomory: **+33** problems across the 6 `random_hammers x
int_hammer_period` cells (5/6 cells improve).
- New trigger (`dio_gomory_enable_period=32`, random): **6417** vs the
period-16 baseline **6409**; no short-cutoff regression.
- Linear `dio_calls_period` recovery: keeping it on is worth ~+20 vs
off; `decrease=1` slightly ahead of the default 2.
Default behavior (`dio_gomory_enable_period=16`) is byte-for-byte
equivalent to the previous threshold logic.
## Notes
Debug-only tracing used during analysis (the `dio_calls_period_trace`
parameter plus per-hammer / period-evolution verbose output) is **not**
included.
---------
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Implemented the largest cube heuristic from Bromberger and Weidenbach's
paper on cubes. Also fixes an overflow bug in mzp.
Use vswhere to find the visual studio version on windows in the build's ymls.
---------
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
#7791 reports on using model values during lex optimization that break soft constraints.
This is an artifact of using optimization where optimal values can be arbitrarily close to a rational.
In a way it is by design, but we give the user now an option to control the starting point for epsilon when converting infinitesimals into rationals.
* rename ul_pair to column
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
* t
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
* simple test passed
* remove an assert
* relax an assertion
* remove an obsolete function
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
* access a term by the term column
* remove the column index from colunm.h
* remove an unused method
* remove debug code
* fix the build of lp_tst
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
---------
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
Co-authored-by: Lev Nachmanson <levnach@hotmail.com>
set UNIT_PROPAGATE_BOUNDS 1 to use the unit propagation version. It applies unit propagation eagerly (does not depend on checking LIA consistency before final check) and avoid creating new literals in most cases
