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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198// * -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/* * Main authors: * Gleb Belov <gleb.belov@monash.edu> */
/* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was ! distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* This is the main file for a mzn-cplex solver using a unified * linearization module && a flexible flattener-to-solver interface */
/// TODO Quadratic terms, even CBC
#ifdef _MSC_VER#define _CRT_SECURE_NO_WARNINGS#endif
#include <chrono>#include <fstream>#include <iomanip>#include <iostream>#include <memory>#include <string>
using namespace std;
#include <minizinc/algorithms/min_cut.h>#include <minizinc/solvers/MIP/MIP_solverinstance.hh>
std::string MIP_wrapper::getMznLib() { return "-Glinear"; }
namespace MiniZinc {namespace SCIPConstraints {
bool CheckAnnUserCut(const Call* call) { if (!call->ann().isEmpty()) { if (call->ann().contains(constants().ann.user_cut)) { return true; } } return false;}bool CheckAnnLazyConstraint(const Call* call) { if (!call->ann().isEmpty()) { if (call->ann().contains(constants().ann.lazy_constraint)) { return true; } } return false;}int GetMaskConsType(const Call* call) { int mask = 0; const bool fUC = CheckAnnUserCut(call); const bool fLC = CheckAnnLazyConstraint(call); if (fUC) { mask |= MIP_wrapper::MaskConsType_Usercut; } if (fLC) { mask |= MIP_wrapper::MaskConsType_Lazy; } if (!fUC && !fLC) mask |= MIP_wrapper::MaskConsType_Normal; return mask; // return MIP_wrapper::MaskConsType_Normal; // recognition fails}} // namespace SCIPConstraints} // namespace MiniZinc
using namespace MiniZinc;
void XBZCutGen::generate(const MIP_wrapper::Output& slvOut, MIP_wrapper::CutInput& cutsIn) { assert(pMIP); const int n = static_cast<int>(varX.size()); assert(n == varB.size()); MIP_wrapper::CutDef cut(MIP_wrapper::GQ, MIP_wrapper::MaskConsType_Usercut); cut.addVar(varZ, -1.0); for (int i = 0; i < n; ++i) { const int ix = varX[i]; const int ib = varB[i]; assert(ix >= 0 && ix < slvOut.nCols); assert(ib >= 0 && ib < slvOut.nCols); const double theXi = slvOut.x[ix]; const double theBi = slvOut.x[ib]; const double LBXi = pMIP->colLB[ix]; const double UBXi = pMIP->colUB[ix]; // tighter bounds from presolve? TODO bool fi = (theXi + LBXi * (theBi - 1.0) - UBXi * theBi < 0.0); if (fi) { cut.addVar(ix, 1.0); cut.addVar(ib, LBXi); cut.rhs += LBXi; } else { cut.addVar(ib, UBXi); } } double dViol = cut.computeViol(slvOut.x, slvOut.nCols); if (dViol > 0.01) { // ?? PARAM? TODO cutsIn.push_back(cut); cerr << " vi" << dViol << flush; // cout << cut.rmatind.size() << ' ' // << cut.rhs << " cutlen, rhs. (Sense fixed to GQ) " << endl; // for ( int i=0; i<cut.rmatind.size(); ++i ) // cout << cut.rmatind[i] << ' '; // cout << endl; // for ( int i=0; i<cut.rmatind.size(); ++i ) // cout << cut.rmatval[i] << ' '; // cout << endl; }}
void XBZCutGen::print(ostream& os) { os << varZ << '\n' << varX.size() << '\n'; for (int i = 0; i < varX.size(); ++i) os << varX[i] << ' '; os << endl; for (int i = 0; i < varB.size(); ++i) os << varB[i] << ' '; os << endl;}
std::string SECCutGen::validate() const { std::ostringstream oss; /// Check that diagonal flows are 0 for (int i = 0; i < nN; ++i) if (pMIP->colUB[varXij[i * nN + i]] > 0.0) oss << "SECutGen with " << nN << " cities: diagonal flow " << (i + 1) << " has UB=" << pMIP->colUB[varXij[i * nN + i]] << "\n"; return oss.str();}
void SECCutGen::generate(const MIP_wrapper::Output& slvOut, MIP_wrapper::CutInput& cutsIn) { assert(pMIP); /// Extract graph, converting to undirected typedef map<pair<int, int>, double> TMapFlow; TMapFlow mapFlow; for (int i = 0; i < nN; ++i) { for (int j = 0; j < nN; ++j) { const double xij = slvOut.x[varXij[nN * i + j]]; if (i == j) MZN_ASSERT_HARD_MSG(1e-4 > fabs(xij), "circuit: X[" << (i + 1) << ", " << (j + 1) << "]==" << xij); MZN_ASSERT_HARD_MSG( -1e-4 < xij && 1.0 + 1e-4 > xij, // adjusted from 1e-6 to 1e-4 for CBC. 7.8.19 "circuit: X[" << (i + 1) << ", " << (j + 1) << "]==" << xij); if (1e-4 <= xij) { mapFlow[make_pair(min(i, j), max(i, j))] += xij; } } } /// Invoking Min Cut // cerr << " MIN CUT... " << flush; Algorithms::MinCut mc; mc.nNodes = nN; mc.edges.reserve(mapFlow.size()); mc.weights.reserve(mapFlow.size()); for (const auto& mf : mapFlow) { mc.edges.push_back(mf.first); mc.weights.push_back(mf.second); } mc.solve(); /// Check if violation if (mc.wMinCut <= 1.999) { MIP_wrapper::CutDef cut(MIP_wrapper::GQ, MIP_wrapper::MaskConsType_Lazy | MIP_wrapper::MaskConsType_Usercut); cut.rhs = 1.0; int nCutSize = 0; constexpr int nElemPrint = 20; // cerr << " CUT: [ "; for (int i = 0; i < nN; ++i) if (mc.parities[i]) { ++nCutSize; // if ( nCutSize<=nElemPrint ) // cerr << (i+1) << ", "; // else if ( nCutSize==nElemPrint+1 ) // cerr << "..."; for (int j = 0; j < nN; ++j) if (!mc.parities[j]) { cut.addVar(varXij[nN * i + j], 1.0); } } // cerr << "]. " << flush; double dViol = cut.computeViol(slvOut.x, slvOut.nCols); if (dViol > 0.0001) { // ?? PARAM? TODO. See also min cut value required cutsIn.push_back(cut); /* cerr << " SEC: viol=" << dViol << " N NODES: " << nN << " |X|: : " << nCutSize << flush; */ } else { MZN_ASSERT_HARD_MSG(0, " SEC cut: N nodes = " << nN << ": violation = " << dViol << ": too small compared to the min-cut value " << (2.0 - mc.wMinCut)); } }}
void SECCutGen::print(ostream&) {}