CPLEX - 访问解决方案C++时出错

我在访问 LP 问题的解决方案时遇到问题。

这是调用 cplex.solve() 后 CPLEX 的输出;

CPXPARAM_MIP_Strategy_CallbackReducedLP          0
Found incumbent of value 0.000000 after 0.00 sec. (0.70 ticks)
Tried aggregator 1 time.
MIP Presolve eliminated 570 rows and 3 columns.
MIP Presolve modified 88 coefficients.
Reduced MIP has 390 rows, 29291 columns, and 76482 nonzeros.
Reduced MIP has 29291 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.06 sec. (49.60 ticks)
Tried aggregator 1 time.
Reduced MIP has 390 rows, 29291 columns, and 76482 nonzeros.
Reduced MIP has 29291 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.04 sec. (31.47 ticks)
Probing time = 0.02 sec. (1.36 ticks)
MIP emphasis: balance optimality and feasibility.
MIP search method: dynamic search.
Parallel mode: deterministic, using up to 8 threads.
Root relaxation solution time = 0.03 sec. (17.59 ticks)
Nodes                                         Cuts/
Node  Left     Objective  IInf  Best Integer    Best Bound    ItCnt     Gap
*     0+    0                            0.0000     -395.1814              --- 
*     0+    0                         -291.2283     -395.1814            35.69%
*     0     0      integral     0     -372.2283     -372.2283      201    0.00%
Elapsed time = 0.21 sec. (131.64 ticks, tree = 0.00 MB, solutions = 3)
Root node processing (before b&c):
Real time             =    0.21 sec. (133.18 ticks)
Parallel b&c, 8 threads:
Real time             =    0.00 sec. (0.00 ticks)
Sync time (average)   =    0.00 sec.
Wait time (average)   =    0.00 sec.
------------
Total (root+branch&cut) =    0.21 sec. (133.18 ticks)

但是，当我调用cplex.getValues(values，variables)时，程序会给出一个SIGABRT信号，抛出以下异常：

libc++abi.dylib: terminating with uncaught exception of type IloAlgorithm::NotExtractedException

这是我的代码。我做错了什么？

std::vector<links_t> links(pointsA.size()*pointsB.size());
std::unordered_map<int, std::vector<std::size_t> > point2DToLinks;
for(std::size_t i=0; i<pointsA.size(); ++i){
for(std::size_t j=0; j<pointsB.size(); ++j){
std::size_t index = (i*pointsA.size()) + j;
links[index].from = i;
links[index].to   = j;
links[index].value = cv::norm(pointsA[i] - pointsB[j]);
point2DToLinks[pointsA[i].point2D[0]->id].push_back(index);
point2DToLinks[pointsA[i].point2D[1]->id].push_back(index);
point2DToLinks[pointsA[i].point2D[2]->id].push_back(index);
point2DToLinks[pointsB[j].point2D[0]->id].push_back(index);
point2DToLinks[pointsB[j].point2D[1]->id].push_back(index);
point2DToLinks[pointsB[j].point2D[2]->id].push_back(index);
}
}
std::size_t size = links.size() + point2DToLinks.size();
IloEnv environment;
IloNumArray coefficients(environment, size);
for(std::size_t i=0; i<links.size(); ++i)    coefficients[i] = links[i].value;
for(std::size_t i=links.size(); i<size; ++i) coefficients[i] = -lambda;
IloNumVarArray variables(environment, size, 0, 1, IloNumVar::Bool);
IloObjective objective(environment, 0.0, IloObjective::Minimize);
objective.setLinearCoefs(variables, coefficients);
IloRangeArray constrains = IloRangeArray(environment);
std::size_t counter = 0;
for(auto point=point2DToLinks.begin(); point!=point2DToLinks.end(); point++){
IloExpr expression(environment);
const std::vector<std::size_t> & inLinks = point->second;
for(std::size_t j=0; j<inLinks.size(); j++) expression += variables[inLinks[j]];
expression -= variables[links.size() + counter];
constrains.add(IloRange(environment, 0, expression));
expression.end();
++counter;
}
IloModel model(environment);
model.add(objective);
model.add(constrains);
IloCplex cplex(model);
cplex.solve();
if(cplex.getStatus() != IloAlgorithm::Optimal){
fprintf(stderr, "error: cplex terminate with an error.n");
abort();
}
IloNumArray values(environment, size);
cplex.getValues(values, variables);
for(std::size_t i=0; i<links.size(); ++i)
if(values[i] > 0) pairs.push_back(links[i]);
environment.end();