Originally posted by: SystemAdmin

Hello,

I'm reaching out to some concert c++ users out there. I can't figure out why this code fails when trying to add second variable. I basically mixed together differents parts of code I found on the net.

The main method basically maps cplex variable to indexes. Displaying the original data matrix works fine so the mapping is correct...

Thank you in advance!

// MwC.cpp : Defines the entry point for the console application.
//

#include <vector>
#include<map>

#include <ilcplex/ilocplex.h>
ILOSTLBEGIN

static void usage (const char *progname);
IloInt _row_num;
IloInt _var_num;

IloInt _res_row_num;
IloInt _res_var_num;

std::vector<IloNum> _res_cap; // residual capacity of variable

struct VARIABLE {
IloInt id;
std::vector<IloNum> column_data;
IloNum obj_coef;

VARIABLE(IloInt idvalue)
{
id = idvalue;

column_data.assign(_row_num + 1, 0); // assume empty
column_data[0] = 1;
//column_data.push_back(1); // convexity constraint
}

VARIABLE() {
id = -1;
column_data.assign(_row_num + 1, 0); // assume empty
column_data[0] = 1;
//column_data.push_back(1); // convexity constraint

//column_data.reserve(_row_num + 1);
//column_data.assign(_row_num, 0);
//column_data.push_back(1);
}
};

struct ROW {
IloInt id;
unsigned int order;
IloNum rhs;

ROW(IloInt idvalue, unsigned int orderval, IloNum rhsvalue) {
id = idvalue;
order = orderval;
rhs = rhsvalue;
}

ROW() {}
};
std::map<const char*, ROW> ROWIDX;
std::map<const char*, VARIABLE> VARIDX;

void displayobj(IloNumVarArray& v) {
IloEnv env = v.getEnv();

for(int i = 0 ; i < _var_num ; ++i) {
env.out() << VARIDX[ vhttp://i].getName() .obj_coef << ", ";
}
env.out() << endl;
}

void displaymatrix(IloNumVarArray& v, IloRangeArray& c) {
IloEnv env = v.getEnv();

env.out() << "DATA MATRIX: " << endl;
for(int j = 0 ; j < _row_num ; ++j) {
for(int i = 0 ; i < _var_num ; ++i) {
env.out() << VARIDX[ vhttp://i].getName() .column_data[ ROWIDX[ chttp://j].getName()].order << ", ";
}
env.out() << "||" << ROWIDX[chttp://j].getName().rhs << endl;
}
}

void displayLP(IloNumVarArray& v, IloRangeArray& c) {
displayobj(v);
displaymatrix(v, c);
}

void doubleUp(IloModel& model, IloNumVarArray& orig_var, IloRangeArray& orig_c, IloModel& c_model, IloObjective& c_obj, IloNumVarArray& c_vars, IloRangeArray& c_cons) {
// model :
// Ax = b
// l <= x <= u
// Exit with c_model :
// build Ay + Aw = 0
// 1y + 1w = 1
// 0 <= y <= 1
// 0 <= w <= 1
IloEnv env = model.getEnv();
IloEnv newenv = c_model.getEnv();

// add information to respective Ilo*

c_obj = IloMinimize(newenv);

env.out() << "c" << endl;

// Constraint
c_cons.add(IloRange(newenv, 1., 1., "convexity")); // add convexity
for(int i = 0 ; i < _row_num ; ++i ) {
c_cons.add ( IloRange( newenv, 0. , 0., orig_c[i].getName())); // same "set" of constraint as ORIG
env.out() << "order: " << ROWIDX[ orig_chttp://i].getName() .order << endl;
}
env.out() << "cons size: " << c_cons.getSize() << endl;

c_model.add(c_obj);
c_model.add(c_cons);

env.out() << "v" << endl;
for(int i = 0 ; i < _var_num ; ++i) {
IloNumColumn expr = c_obj (VARIDX[orig_varhttp://i].getName().obj_coef) + c_cons[0](1);
env.out() << VARIDX[orig_varhttp://i].getName().obj_coef << ", ";
for(int r = 0 ; r < _row_num ; ++r) {
env.out() << VARIDX[orig_varhttp://i].getName().column_data[ ROWIDX[ orig_chttp://r].getName() ].order << ", ";
expr += c_cons[ ROWIDX[ orig_chttp://r].getName() ].order ( VARIDX[orig_varhttp://i].getName().column_data[ ROWIDX[ orig_chttp://r].getName() ].order );
}
env.out() << endl;

env.out() << "try add" << endl;
IloNumVar x(expr, 0.0, 1.0); // program crashes here on second loop

env.out() << orig_var[i].getName() << endl;

x.setName(orig_var[i].getName());
c_vars.add(x);

//c_vars.add( IloNumVar( expr, 0.0, 1.0));

expr.end();

char* t;
strcpy(t, orig_var[i].getName());
strcat(t, "copy");

//env.out() << "conc"<<endl;

//IloNumColumn expr2(env);
/*expr2 = c_obj (VARIDX[orig_varhttp://i].getName().obj_coef) + c_cons[0](1.);
for(int r = 0 ; r < _row_num ; ++r) {
expr2 += c_cons r + 1 ( VARIDX[orig_varhttp://i].getName().column_data[ ROWIDX[ orig_chttp://r].getName() ].order );
}*/
//env.out() << "exor:" << endl;
//IloNumVar x2(expr2, 0.0, 1.0);
//env.out() << "x2" <<endl;
//x2.setName( t);
//env.out() << "second" << endl;
}

env.out() << "m" << endl;

env.out() << "done" << endl;

IloCplex cp(newenv);
cp.extract(c_model);
env.out() << "ex" << endl;

//IloCplex cp(c_model);
cp.exportModel("testoutput.lp");
cp.end();

}

int _tmain(int argc, _TCHAR* argv[])
{
IloEnv env;

try {
IloModel model(env);
IloCplex cplex(env);

cplex.setParam(IloCplex::RootAlg, IloCplex::Primal);

IloObjective obj;
IloNumVarArray var(env);
IloRangeArray rng(env);
cplex.importModel(model, "mittel/test4.mps", obj, var, rng);
cplex.extract(model);

_var_num = var.getSize();
_row_num = rng.getSize();

env.out() << "nb var: " << _var_num << " nb row: " << _row_num << endl;

// map variable names and id
for(int i = 0 ; i < _var_num ; ++i) {
VARIABLE v( var[i].getId());
VARIDX.insert(pair<const char*, VARIABLE>(var[i].getName() , v));
}
// map row names and id
unsigned int o = 0;
for(int i = 0 ; i < _row_num ; ++i) {
ROW r(rng[i].getId(), ++o, rng[i].getUB());
ROWIDX.insert(pair<const char*, ROW> ( rng[i].getName() , r));
}
// ROWIDX.insert(pair<const char*, ROW> ("convexity", 0)); // convexity constraint will be id = 0

// fill internal data matrix
for(int i = 0 ; i < rng.getSize() ; ++i) {
//cout << "row:" << rng[i].getName() << " id: " << rng[i].getId() << endl;
for (IloExpr::LinearIterator it = IloExpr(rng[i].getExpr()).getLinearIterator() ; it.ok() ; ++it) {
//env.out() << "variable id: "<< it.getVar().getId() << " var name: " << it.getVar().getName() << " coef: "<< it.getCoef() << endl;
//env.out() << "matching id: " << VARIDXhttp://it.getVar().getName().id << endl;
VARIDXhttp://it.getVar().getName().column_data[ ROWIDX[ rnghttp://i].getName()].order = it.getCoef();
}
}

// fill obj data
for(IloExpr::LinearIterator it = IloExpr(obj.getExpr()).getLinearIterator() ; it.ok() ; ++it) {
//env.out() << "variable id: "<< it.getVar().getId() << " var name: " << it.getVar().getName() << " coef: "<< it.getCoef() << endl;
//env.out() << "matching id: " << VARIDXhttp://it.getVar().getName().id << endl;
VARIDXhttp://it.getVar().getName().obj_coef = it.getCoef();
}

displayLP(var, rng);

// Create new model
//IloEnv env2 = env;
IloObjective obj2;
IloModel model2(env);
IloNumVarArray var2(env);
IloRangeArray rng2(env);

doubleUp(model, var, rng, model2, obj2, var2, rng2);
if ( !cplex.solve() ) {
env.error() << "Failed to optimize LP" << endl;
throw(-1);
}

IloNumArray vals(env);
cplex.getValues(vals, var);
env.out() << "Solution status = " << cplex.getStatus() << endl;
env.out() << "Solution value = " << cplex.getObjValue() << endl;

// env.out() << "Solution vector = " << vals << endl;
// try { // basis may not exist
// IloCplex::BasisStatusArray cstat(env);
//cplex.getBasisStatuses(cstat, var);
// //cplex.getStatuses(cstat, var);
// env.out() << "Basis statuses = " << cstat << endl;
// } catch (...) {
// }

env.out() << "Maximum bound violation = "
<< cplex.getQuality(IloCplex::MaxPrimalInfeas) << endl;
}
catch (IloException& e) {
cerr << "Concert exception caught: " << e << endl;
}
catch (...) {
cerr << "Unknown exception caught" << endl;
}

env.end();
return 0;
} // END main
static void usage (const char *progname)
{
cerr << "Usage: " << progname << " filename algorithm" << endl;
cerr << " where filename is a file with extension " << endl;
cerr << " MPS, SAV, or LP (lower case is allowed)" << endl;
cerr << " and algorithm is one of the letters" << endl;
cerr << " o default" << endl;
cerr << " p primal simplex" << endl;
cerr << " d dual simplex " << endl;
cerr << " b barrier " << endl;
cerr << " h barrier with crossover" << endl;
cerr << " n network simplex" << endl;
cerr << " Exiting..." << endl;
} // END usage
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

Bah, the interpreter messed up the encoding. Here it is attached.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

It would be helpful if you told us what exactly the problem is (error message, crash report, does not compile) and which line of code triggers the problem.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

Sorry. I thought I did but apparently I did attach the right commented file. A new one more clean is attached now.

It crashes in the method doubleUp, which is the purpose of the code. Make a very similar model as the original.

It crashes exactly in the for loop when I add variables on i = 1. (ie first variable is added fine) which also creates the expected model if I use break;

I'm using Visual Studio 2010.

It crash message is Unhandled exception at 0x000000013f700d18 in MwC.exe: 0xC0000005: Access violation reading location 0x000079706f6331a8.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

One thing that looks extremely weird in your code is this:

// eventually will add another variable...
char* t;
strcpy(t, orig_var[i].getName());
strcat(t, "copy");

It looks like you are trying to concatenate the variable name and the string "copy". But you are doing this in the wrong way. 't' is not initialized and strcpy() will attempt to copy data into this uninitialized pointer and this will result in memory corruption or a crash. I suggest to that like this:

std::string t(orig_var[i].getName());
t += "copy";

This will correctly concatenate the strings. The concatenation is available as C-style string via 't.c_str()'.
Does this fix your problem?
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

Yes it does. Thank you!
#CPLEXOptimizers
#DecisionOptimization