bool SplitEquation( CoeffVec& cur,
const SymbolicVal& cut, const BoundVec& bounds,
BoundOp& boundop, CoeffVec& split)
{
int dim = cur.size()-1;
SymbolicVal leftval = cur[dim]; // obtain the last coefficient, which is right side terms without using loop index variable
if (leftval != 0) {
CompareRel r1 = CompareVal(leftval,-cut, &boundop);
CompareRel r2 = CompareVal(leftval,cut, &boundop);
bool lt = ((r1 & REL_GT) && (r2 & REL_LT)) || ((r1 & REL_LT) && (r2 & REL_GT));
if (!lt) { // relation of r1 and r2 must be reversed pair, or error
if (DebugDep())
std::cerr << "unable to split because " << leftval.toString() << " ? " << cut.toString() << std::endl;
return false;
}
}
bool succ = false;
split.clear();
int j =0;
for (; j < dim; ++j) {
SymbolicVal left = cur[j] / cut;
if (HasFraction(left))
split.push_back(0);
else {
split.push_back(left);
succ = true;
}
}
split.push_back(0); // right-hand side value
if (succ) {
SymbolicVal left = 0;
for (j = 0; j < dim; ++j) {
if (split[j]== 0)
switch (CompareVal(cur[j],0,&boundop)) {
case REL_LE:
left = left + cur[j] * bounds[j].lb; break;
case REL_GE:
left = left + cur[j] * bounds[j].ub; break;
default: break;
}
}
if (j == dim && (left == 0 || (CompareVal(left,cut) & REL_LT))) {
for (j = 0; j < dim; ++j) {
if (split[j] != 0)
cur[j] = 0; // clear some coefficency values
}
return true;
}
else if (DebugDep()) {
if (j == dim)
std::cerr << "unable to decide left " << left.toString() << " ? " << cut.toString() << std::endl;
else
std::cerr << "unable to decide cur[" << j << "] ? 0\n";
}
}
split.clear();
return false;
}
SymbolicVal Min( const SymbolicVal &v1, const SymbolicVal &v2,
MapObject<SymbolicVal, SymbolicBound>* f)
{ if (v1.IsNIL())
return v2;
if (v2.IsNIL())
return v1;
switch (CompareVal(v1,v2,f)) {
case REL_NONE:
case REL_UNKNOWN:
case REL_NE:
{
SelectApplicator minOp(-1);
return ApplyBinOP(minOp,v1,v2);
}
case REL_EQ:
case REL_LT:
case REL_LE:
return v1;
case REL_GT:
case REL_GE:
return v2;
default:
assert(0);
}
}
bool operator > (const SymbolicVal &v1, const SymbolicVal& v2)
{ return CompareVal(v1,v2) == REL_GT; }
