template<class T, class Rounding> inline
T pow_dn(const T& x_, int pwr, Rounding& rnd) // x and pwr are positive
{
T x = x_;
T y = (pwr & 1) ? x_ : static_cast<T>(1);
pwr >>= 1;
while (pwr > 0) {
x = rnd.mul_down(x, x);
if (pwr & 1) y = rnd.mul_down(x, y);
pwr >>= 1;
}
return y;
}
forceinline ExecStatus
MultPlus<VA,VB,VC>::post(Home home, VA x0, VB x1, VC x2) {
GECODE_ME_CHECK(x0.gq(home,0.0));
GECODE_ME_CHECK(x1.gq(home,0.0));
Rounding r;
GECODE_ME_CHECK(x2.gq(home,r.mul_down(x0.min(),x1.min())));
(void) new (home) MultPlus<VA,VB,VC>(home,x0,x1,x2);
return ES_OK;
}
forceinline Gecode::FloatNum
RandomAssignment::randval(void) {
using namespace Gecode;
using namespace Gecode::Float;
Rounding r;
return
r.add_down(
d.min(),
r.mul_down(
r.div_down(
Base::rand(static_cast<unsigned int>(Gecode::Int::Limits::max)),
static_cast<FloatNum>(Gecode::Int::Limits::max)
),
r.sub_down(d.max(),d.min())
)
);
}
ExecStatus
Mult<View>::propagate(Space& home, const ModEventDelta&) {
Rounding r;
if (pos(x0)) {
if (pos(x1) || pos(x2)) goto rewrite_ppp;
if (neg(x1) || neg(x2)) goto rewrite_pnn;
goto prop_pxx;
}
if (neg(x0)) {
if (neg(x1) || pos(x2)) goto rewrite_nnp;
if (pos(x1) || neg(x2)) goto rewrite_npn;
goto prop_nxx;
}
if (pos(x1)) {
if (pos(x2)) goto rewrite_ppp;
if (neg(x2)) goto rewrite_npn;
goto prop_xpx;
}
if (neg(x1)) {
if (pos(x2)) goto rewrite_nnp;
if (neg(x2)) goto rewrite_pnn;
goto prop_xnx;
}
assert(any(x0) && any(x1));
GECODE_ME_CHECK(x2.lq(home,std::max(r.mul_up(x0.max(),x1.max()),
r.mul_up(x0.min(),x1.min()))));
GECODE_ME_CHECK(x2.gq(home,std::min(r.mul_down(x0.min(),x1.max()),
r.mul_down(x0.max(),x1.min()))));
if (pos(x2)) {
if (r.div_up(x2.min(),x1.min()) < x0.min())
GECODE_ME_CHECK(x0.gq(home,0));
if (r.div_up(x2.min(),x0.min()) < x1.min())
GECODE_ME_CHECK(x1.gq(home,0));
}
if (neg(x2)) {
if (r.div_up(x2.max(),x1.max()) < x0.min())
GECODE_ME_CHECK(x0.gq(home,0));
if (r.div_up(x2.max(),x0.max()) < x1.min())
GECODE_ME_CHECK(x1.gq(home,0));
}
if (x0.assigned()) {
assert((x0.val() == 0.0) && (x2.val() == 0.0));
return home.ES_SUBSUMED(*this);
}
if (x1.assigned()) {
assert((x1.val() == 0.0) && (x2.val() == 0.0));
return home.ES_SUBSUMED(*this);
}
return ES_NOFIX;
prop_xpx:
std::swap(x0,x1);
prop_pxx:
assert(pos(x0) && any(x1) && any(x2));
GECODE_ME_CHECK(x2.lq(home,r.mul_up(x0.max(),x1.max())));
GECODE_ME_CHECK(x2.gq(home,r.mul_down(x0.max(),x1.min())));
if (pos(x2)) goto rewrite_ppp;
if (neg(x2)) goto rewrite_pnn;
GECODE_ME_CHECK(x1.lq(home,r.div_up(x2.max(),x0.min())));
GECODE_ME_CHECK(x1.gq(home,r.div_down(x2.min(),x0.min())));
if (x0.assigned() && x1.assigned()) {
GECODE_ME_CHECK(x2.eq(home,x0.val()*x1.val()));
return home.ES_SUBSUMED(*this);
}
return ES_NOFIX;
prop_xnx:
std::swap(x0,x1);
prop_nxx:
assert(neg(x0) && any(x1) && any(x2));
GECODE_ME_CHECK(x2.lq(home,r.mul_up(x0.min(),x1.min())));
GECODE_ME_CHECK(x2.gq(home,r.mul_down(x0.min(),x1.max())));
if (pos(x2)) goto rewrite_nnp;
if (neg(x2)) goto rewrite_npn;
if (x0.max() != 0.0) {
GECODE_ME_CHECK(x1.lq(home,r.div_up(x2.min(),x0.max())));
GECODE_ME_CHECK(x1.gq(home,r.div_down(x2.max(),x0.max())));
}
if (x0.assigned() && x1.assigned()) {
GECODE_ME_CHECK(x2.eq(home,x0.val()*x1.val()));
return home.ES_SUBSUMED(*this);
}
return ES_NOFIX;
rewrite_ppp:
GECODE_REWRITE(*this,(MultPlus<FloatView,FloatView,FloatView>
::post(home(*this),x0,x1,x2)));
rewrite_nnp:
GECODE_REWRITE(*this,(MultPlus<MinusView,MinusView,FloatView>
::post(home(*this),MinusView(x0),MinusView(x1),x2)));
rewrite_pnn:
std::swap(x0,x1);
rewrite_npn:
GECODE_REWRITE(*this,(MultPlus<MinusView,FloatView,MinusView>
::post(home(*this),MinusView(x0),x1,MinusView(x2))));
}