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pb/car constraints

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2013-11-07 00:53:08 -08:00
parent 55e91c099f
commit 3ee8c3efb5
6 changed files with 494 additions and 298 deletions
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99
src/util/sorting_network.h Normal file
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#include "vector.h"
#ifndef _SORTING_NETWORK_H_
#define _SORTING_NETWORK_H_
template <typename Ext>
class sorting_network {
typename Ext::vector& m_es;
Ext& m_ext;
svector<unsigned> m_currentv;
svector<unsigned> m_nextv;
svector<unsigned>* m_current;
svector<unsigned>* m_next;
unsigned& current(unsigned i) { return (*m_current)[i]; }
unsigned& next(unsigned i) { return (*m_next)[i]; }
void exchange(unsigned i, unsigned j) {
SASSERT(i <= j);
if (i < j) {
Ext::T ei = m_es.get(i);
Ext::T ej = m_es.get(j);
m_es.set(i, m_ext.mk_ite(m_ext.mk_le(ei, ej), ei, ej));
m_es.set(j, m_ext.mk_ite(m_ext.mk_le(ej, ei), ei, ej));
}
}
void sort(unsigned k) {
SASSERT(is_power_of2(k) && k > 0);
if (k == 2) {
for (unsigned i = 0; i < m_es.size()/2; ++i) {
exchange(current(2*i), current(2*i+1));
next(2*i) = current(2*i);
next(2*i+1) = current(2*i+1);
}
std::swap(m_current, m_next);
}
else {
for (unsigned i = 0; i < m_es.size()/k; ++i) {
unsigned ki = k * i;
for (unsigned j = 0; j < k / 2; ++j) {
next(ki + j) = current(ki + (2 * j));
next(ki + (k / 2) + j) = current(ki + (2 * j) + 1);
}
}
std::swap(m_current, m_next);
sort(k / 2);
for (unsigned i = 0; i < m_es.size() / k; ++i) {
unsigned ki = k * i;
for (unsigned j = 0; j < k / 2; ++j) {
next(ki + (2 * j)) = current(ki + j);
next(ki + (2 * j) + 1) = current(ki + (k / 2) + j);
}
for (unsigned j = 0; j < (k / 2) - 1; ++j) {
exchange(next(ki + (2 * j) + 1), next(ki + (2 * (j + 1))));
}
}
std::swap(m_current, m_next);
}
}
bool is_power_of2(unsigned n) const {
return n != 0 && ((n-1) & n) == 0;
}
public:
sorting_network(Ext& ext, typename Ext::vector& es):
m_ext(ext),
m_es(es),
m_current(&m_currentv),
m_next(&m_nextv)
{}
void operator()(typename Ext::vector const& inputs) {
if (inputs.size() <= 1) {
return;
}
m_es.reset();
m_es.append(inputs);
while (!is_power_of2(m_es.size())) {
m_es.push_back(m_ext.mk_default());
}
for (unsigned i = 0; i < m_es.size(); ++i) {
current(i) = i;
}
unsigned k = 2;
while (k <= m_es.size()) {
sort(k);
k *= 2;
}
}
};
#endif