Hi,
Thanks for the bit of code, it worked perfectly fine ! It helped me found
my newbie mistake. I was checking if I found any solution by doing :
if (solutions.next() ==NULL){
os<<"No solutions"<<endl;
return false;
}
while(RMModel *solution = solutions.next())
{
solution->print(os);
delete solution;}
In restrospect that was a very stupid way of doing it. So my code did in
fact find the right solutions, it just skipped the first one, while
checking if it found a solution in the first place.
Another question loosely related to my initial problem of not finding all
solutions : is it usual for the BAB search engine to not give the same
number of solutions (I have one less) than the DFS. I modified your file to
reproduce this"problem", and attached it to this mail. Maybe this is how it
is supposed to work.
Thanks again for your help,
Baptiste
#include <gecode/driver.hh>
#include <gecode/int.hh>
#include <gecode/minimodel.hh>
using namespace Gecode;
class CumulativesTest : public MaximizeSpace {
public:
IntVarArray x;
IntVar CostValue;
CumulativesTest() : x(*this,6,0,10),CostValue(*this,1,1) {
IntVarArgs start(3);
IntVarArgs end(3);
IntVarArgs CostCoefficient(3);
IntArgs m(3);
IntArgs p(3);
IntArgs u(3);
IntArgs c(1);
c[0] = 0;
int machine[3] = {0,0,0};
int duration[3] = {5,5,10};
int capacity[3] = {-3,-9,10};
int earlyStart[3] = {0,0,0};
int lateStart[3] = {10,10,0};
for(int i = 0;i<3;i++){
m[i] = machine[i];
p[i] = duration[i];
u[i] = capacity[i];
start[i] = x[i];
end[i] = x[i+3];
rel(*this,start[i]<=lateStart[i]);
rel(*this,start[i]>=earlyStart[i]);
rel(*this, start[i]+p[i]==end[i]);
// The cost of source is 0
CostCoefficient[i] = expr(*this,
(start[i]+1)*capacity[i]*(earlyStart!=lateStart)
);
}
cumulatives(*this, m,start,p,end,u,c,false);
//Compute cost of the problem
CostValue = expr(*this,sum(CostCoefficient));
branch(*this, end, INT_VAR_MAX_MAX, INT_VAL_MAX);
branch(*this, start, INT_VAR_MIN_MIN, INT_VAL_MIN);
}
CumulativesTest(bool share, CumulativesTest& s) : MaximizeSpace(share,s) {
x.update(*this, share, s.x);
}
virtual Space*
copy(bool share) {
return new CumulativesTest(share,*this);
}
IntVar cost(void) const { return CostValue;}
/// Print solution
virtual void
print(std::ostream& os) const {
os << x <<std::endl;
}
};
int
main(int argc, char* argv[]) {
CumulativesTest* DFSmodel = new CumulativesTest;
std::cout<<"DFS"<<std::endl;
DFS<CumulativesTest> DFSsolutions(DFSmodel);
while(CumulativesTest *DFSsolution = DFSsolutions.next())
{
DFSsolution->print(std::cout);
delete DFSsolution;
}
delete DFSmodel;
std::cout<<"BAB"<<std::endl;
CumulativesTest* BABmodel = new CumulativesTest;
BAB<CumulativesTest> BABsolutions(BABmodel);
while(CumulativesTest *BABsolution = BABsolutions.next())
{
BABsolution->print(std::cout);
delete BABsolution;
}
delete BABmodel;
return 0;
}
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