solvers.py 文件源码

def actualSolve(self, lp):
        """Solve a well formulated lp problem"""
        if not self.executable(self.path):
            raise PulpSolverError("PuLP: cannot execute "+self.path)

        # TODO: should we use tempfile instead?
        if not self.keepFiles:
            pid = os.getpid()
            tmpLp = os.path.join(self.tmpDir, "%d-pulp.lp" % pid)
            tmpSol = os.path.join(self.tmpDir, "%d-pulp.sol" % pid)
        else:
            tmpLp = lp.name + "-pulp.lp"
            tmpSol = lp.name + "-pulp.sol"

        lp.writeLP(tmpLp)
        proc = [
            'scip', '-c', 'read "%s"' % tmpLp, '-c', 'optimize',
            '-c', 'write solution "%s"' % tmpSol, '-c', 'quit'
        ]
        proc.extend(self.options)
        if not self.msg:
            proc.append('-q')

        self.solution_time = clock()
        subprocess.check_call(proc, stdout=sys.stdout, stderr=sys.stderr)
        self.solution_time += clock()

        if not os.path.exists(tmpSol):
            raise PulpSolverError("PuLP: Error while executing "+self.path)

        lp.status, values = self.readsol(tmpSol)

        # Make sure to add back in any 0-valued variables SCIP leaves out.
        finalVals = {}
        for v in lp.variables():
            finalVals[v.name] = values.get(v.name, 0.0)

        lp.assignVarsVals(finalVals)

        if not self.keepFiles:
            for f in (tmpLp, tmpSol):
                try:
                    os.remove(f)
                except:
                    pass

        return lp.status