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/* Copyright (c) 1997-2020
Ewgenij Gawrilow, Michael Joswig, and the polymake team
Technische Universität Berlin, Germany
https://polymake.org
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version: http://www.gnu.org/licenses/gpl.txt.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
--------------------------------------------------------------------------------
*/
#ifndef __POLYMAKE_POLY2LP_H__
#define __POLYMAKE_POLY2LP_H__
#include "polymake/Rational.h"
#include "polymake/SparseMatrix.h"
#include "polymake/SparseVector.h"
#include "polymake/Array.h"
#include <fstream>
namespace polymake { namespace polytope {
namespace {
template <typename Vector>
void print_row(std::ostream& os,
const std::string& tag,
Int index,
const GenericVector<Vector>& v,
const Array<std::string>& variable_names,
const char* relop = nullptr)
{
if (v == unit_vector<typename Vector::element_type>(v.dim(),0)) // don't print the line " 0 >= -1 "
return;
auto e = entire(v.top());
typename Vector::element_type free_term(0);
if (!e.at_end() && e.index()==0) {
free_term=*e; ++e;
}
os << " " << tag;
if (tag != "obj") os << index;
os << ":";
while (!e.at_end()) {
os << ' ' << std::setiosflags(std::ios::showpos) << convert_to<double>(*e) << std::resetiosflags(std::ios::showpos)
<< ' ' << variable_names[e.index()-1];
++e;
}
if (relop) {
os << ' ' << relop << ' ' << convert_to<double>(-free_term);
} else if (!is_zero(free_term)) {
os << ' ' << std::setiosflags(std::ios::showpos) << convert_to<double>(free_term) << std::resetiosflags(std::ios::showpos);
}
os << '\n';
}
} // end anonymous namespace
template<typename Scalar=Rational>
void print_lp(BigObject p, BigObject lp, const bool maximize, std::ostream& os)
{
const Int is_feasible=p.give("FEASIBLE");
const SparseMatrix<Scalar>
IE = p.give("FACETS | INEQUALITIES"),
EQ = p.lookup("AFFINE_HULL | EQUATIONS");
const SparseVector<Scalar> LO = lp.give("LINEAR_OBJECTIVE");
const Int n_variables = IE.cols()-1;
if (!is_feasible)
throw std::runtime_error("input is not FEASIBLE");
Array<std::string> variable_names;
if (lp.get_attachment("VARIABLE_NAMES") >> variable_names) {
if (variable_names.size() != n_variables)
throw std::runtime_error("dimension mismatch between the polytope and VARIABLE_NAMES");
} else {
variable_names.resize(n_variables);
for (Int j=0; j < n_variables; ++j)
variable_names[j]='x' + std::to_string(j+1);
}
Array<bool> integers = lp.get_attachment("INTEGER_VARIABLES");
os << std::setprecision(16)
<< (maximize ? "MAXIMIZE\n" : "MINIMIZE\n");
print_row(os, "obj", 0, LO, variable_names);
os << "Subject To\n";
for (auto ie=entire(rows(IE)); !ie.at_end(); ++ie) {
print_row(os, "ie", ie.index(), *ie, variable_names, ">=");
}
for (auto eq=entire(rows(EQ)); !eq.at_end(); ++eq) {
print_row(os, "eq", eq.index(), *eq, variable_names, "=");
}
os << "BOUNDS\n";
for (Int i = 0; i < n_variables; ++i)
os << " " << variable_names[i] << " free\n";
if (!integers.empty()) {
os << "GENERAL\n";
for (Int i = 0; i < integers.size(); ++i)
if (integers[i]) os << " " << variable_names[i] << '\n';
}
os << "END" << endl;
}
} }
#endif // __POLYMAKE_POLY2LP_H__
// Local Variables:
// mode:C++
// c-basic-offset:3
// indent-tabs-mode:nil
// End:
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