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[CP-SAT] Use AddExactly/AtMostOne in examples/samples; add int_square presolve; add multiplication constraint with target = left * right

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This commit is contained in:
Laurent Perron
2022-01-01 19:26:39 +01:00
parent b9cd938c16
commit 79f2c45c33
34 changed files with 174 additions and 96 deletions
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29
ortools/sat/integer_expr.cc
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@@ -22,6 +22,7 @@
#include "absl/memory/memory.h"
#include "ortools/base/stl_util.h"
#include "ortools/sat/integer.h"
#include "ortools/sat/util.h"
#include "ortools/util/sorted_interval_list.h"
#include "ortools/util/time_limit.h"
@@ -964,30 +965,6 @@ void ProductPropagator::RegisterWith(GenericLiteralWatcher* watcher) {
watcher->NotifyThatPropagatorMayNotReachFixedPointInOnePass(id);
}
namespace {
// TODO(user): Find better implementation? In pratice passing via double is
// almost always correct, but the CapProd() might be a bit slow. However this
// is only called when we do propagate something.
IntegerValue FloorSquareRoot(IntegerValue a) {
IntegerValue result(static_cast<int64_t>(
std::floor(std::sqrt(static_cast<double>(a.value())))));
while (CapProd(result.value(), result.value()) > a) --result;
while (CapProd(result.value() + 1, result.value() + 1) <= a) ++result;
return result;
}
// TODO(user): Find better implementation?
IntegerValue CeilSquareRoot(IntegerValue a) {
IntegerValue result(static_cast<int64_t>(
std::ceil(std::sqrt(static_cast<double>(a.value())))));
while (CapProd(result.value(), result.value()) < a) ++result;
while ((result.value() - 1) * (result.value() - 1) >= a) --result;
return result;
}
} // namespace
SquarePropagator::SquarePropagator(AffineExpression x, AffineExpression s,
IntegerTrail* integer_trail)
: x_(x), s_(s), integer_trail_(integer_trail) {
@@ -1006,7 +983,7 @@ bool SquarePropagator::Propagate() {
return false;
}
} else if (min_x_square < min_s) {
const IntegerValue new_min = CeilSquareRoot(min_s);
const IntegerValue new_min(CeilSquareRoot(min_s.value()));
if (!integer_trail_->SafeEnqueue(
x_.GreaterOrEqual(new_min),
{s_.GreaterOrEqual((new_min - 1) * (new_min - 1) + 1)})) {
@@ -1023,7 +1000,7 @@ bool SquarePropagator::Propagate() {
return false;
}
} else if (max_x_square > max_s) {
const IntegerValue new_max = FloorSquareRoot(max_s);
const IntegerValue new_max(FloorSquareRoot(max_s.value()));
if (!integer_trail_->SafeEnqueue(
x_.LowerOrEqual(new_max),
{s_.LowerOrEqual(IntegerValue(CapProd(new_max.value() + 1,