Originally posted by: rourou

i am using CP Optimizer V2.3 to solve a fesibility problem. When the amount of feasible solution exceed about 200,000, it threw Standard exception: bad allocation

the main code is below:

IloModel model(env);
IloCP cp(model);
.......
cp.startNewSearch();
while(cp.next())
{
......
}

cp.end();

When the amount of while iteration exceed about 200,000, it threw Standard exception: bad allocation .
How to allocate more memory to this computation?
#CPOptimizer
#DecisionOptimization

Originally posted by: SystemAdmin

Hello,
I think the first think to do is to check that the memory is indeed consumed by CP Optimizer. If you have not done it, you should try printing the CP Optimizer memory usage in the loop and have a look at the memory consumed by CP Optimizer before the exception is thrown:

IloModel model(env); IloCP cp(model); ....... cp.startNewSearch(); 

while(cp.next()) 
{ cp.out() << 
"Memory usage: " << cp.getInfo(IloCP::MemoryUsage) << endl; ...... 
} cp.end();

If the memory used by CP Optimizer really is the reason for the memory exception, then the answer may depend on what exactly you are doing with the solutions (example: only count them or store them somewhere for some future use). In this case, one thing you could consider doing is to partition the solution space by solving several models that consist of the original model plus some partitioning constraints like (x<=k / x>k).

Philippe
#CPOptimizer
#DecisionOptimization

Originally posted by: rourou

thank you very much

when the memory usage reached 3647572, the number didn't change for many iteration. Then the exception is thrown.

So I have to partition the solution space?
#CPOptimizer
#DecisionOptimization

Originally posted by: SystemAdmin

If the peak memory used by CP Optimizer is 3647572 bytes, that is quite few and cannot explain the memory problem I think. Do you allocate something inside the while loop (for instance, store the solution somewhere, ...) ?
You could also try to see if the memory problem happens inside the cp.next() or inside the while loop by printing something when entering and leaving the while section:

IloModel model(env); IloCP cp(model); ....... cp.startNewSearch(); 

while(cp.next()) 
{ cp.out() << 
"Memory usage: " << cp.getInfo(IloCP::MemoryUsage) << endl; cp.out() << 
"Entering section" << endl; ...... cp.out() << 
"Leaving section" << endl; 
} cp.end();

Philippe
#CPOptimizer
#DecisionOptimization

Originally posted by: rourou

Yes, I will show you the full code

IloModel model(env);
IloCP cp(model);
.......
list<int> minX;
list<list<int>> all_minX;
cp.startNewSearch();
while(cp.next())
{
minX.clear();
for(i = 0 ;i < m; i ++)
{
cp.getValue(xk[i]);

if(fabs(tp) < 0.0001)
tp = 0;

if(tp > 0)
{
if((fabs(tp) - (int)(tp+0.5)) < 0.0001)
tp = (int)(tp+0.5);
}

else if(tp < 0)
{
if((fabs(tp) - (int)(tp-0.5)) < 0.0001)
tp = (int)(tp-0.5);
}

minX.push_back(tp);
}

}
cp.end();
#CPOptimizer
#DecisionOptimization

Originally posted by: rourou

the above thread is not right

IloModel model(env);
IloCP cp(model);
.......
list<int> minX;
list<list<int>> all_minX;
cp.startNewSearch();

while(cp.next())
{
minX.clear();

for(i = 0 ;i < m; i ++)
{
minX.push_back(cp.getValue(x[i]));
}

all_minX.push_back(minX);

}
cp.end();
#CPOptimizer
#DecisionOptimization

Originally posted by: SystemAdmin

So I do not know what is the size m of the model, but it seems that the memory is mostly used to store the solutions in your lists all_minX. Isn't it that it just takes too much memory to store all the solutions?

Philippe
#CPOptimizer
#DecisionOptimization

Originally posted by: rourou

yes you are quite right

I delete the all_minX.push_back() and output the solution in a txt file, the exception is gone

thanks you very much.
#CPOptimizer
#DecisionOptimization