Merge pull request #2 from blnicho/solver-rewrite

Adding skeleton of new Ipopt solver (NOT FUNCTIONAL)

pyomo/solver/ipopt.py

@@ -0,0 +1,160 @@
+#  ___________________________________________________________________________
+#
+#  Pyomo: Python Optimization Modeling Objects
+#  Copyright 2017 National Technology and Engineering Solutions of Sandia, LLC
+#  Under the terms of Contract DE-NA0003525 with National Technology and
+#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain
+#  rights in this software.
+#  This software is distributed under the 3-clause BSD License.
+#  ___________________________________________________________________________
+
+from pyutilib.services import TempfileManager
+
+from pyomo.common.config import (
+    ConfigBlock, ConfigList, ConfigValue, add_docstring_list, Path
+)
+from pyomo.common.fileutils import Executable
+from pyomo.solver.base import Solver, SolverResults
+
+
+class IpoptSolver(Solver):
+    CONFIG = Solver.CONFIG()
+
+    def __new__(cls, **kwargs):
+        if cls != IpoptSolver:
+            return super(IpoptSolver, cls).__new__(cls, **kwargs)
+
+        solver_io = kwds.pop('solver_io', 'nl')
+        if config.solver_io == 'nl':
+            return IpoptSolver_NL(**kwargs)
+        else:
+            raise ValueError("Invalid solver_io for IpoptSolver: %s"
+                             % (solver_io,))
+
+
+class IpoptSolver_NL(IpoptSolver):
+    CONFIG = IpoptSolver.CONFIG()
+    CONFIG.declare('executable', ConfigValue(
+        default='ipopt',
+        domain=Executable
+    ))
+    CONFIG.declare("problemfile", ConfigValue(
+        default=None,
+        domain=Path(),
+    ))
+    CONFIG.declare("logfile", ConfigValue(
+        default=None,
+        domain=Path(),
+    ))
+    CONFIG.declare("solnfile", ConfigValue(
+        default=None,
+        domain=Path(),
+    ))
+
+    def available(self):
+        return self.config.executable.path() is not None
+
+    def license_status(self):
+        """
+        Ipopt does not require a license to run so this method is really just
+        an alias of the available method.
+        """
+        return self.available()
+
+    def solve(self, model, options=None, **config_options):
+        """
+        Solve a model
+
+        """
+
+        options = self.options(options)
+        config = self.config(config_options)
+
+        try:
+            TempfileManager.push()
+            return self._apply_solver(model, options, confg)
+        finally:
+            # finally, clean any temporary files registered with the
+            # temp file manager, created/populated *directly* by this
+            # plugin.
+            TempfileManager.pop(remove=not config.keepfiles)
+
+
+    def _apply_solver(self, model, options, config):
+        if not config.problemfile is None:
+            config.problemfile = TempfileManager.create_tempfile(
+                suffix='.pyomo.nl')
+        if not config.logfile:
+            config.logfile = TempfileManager.create_tempfile(
+                suffix='.ipopt.log')
+        if not config.solnfile:
+            config.solnfile = TempfileManager.create_tempfile(
+                suffix='.ipopt.sol')
+
+        # Write out the model
+        writer = WriterFactory(config.solver_io)
+        fname, symbol_map = writer(
+            model=model,
+            output_filename=config.problemfile.path(),
+            solver_capability=lambda x: True,
+            io_options=config.io_options
+        )
+        assert fname == str(config.problemfile)
+
+
+        # Extract Suffixes
+
+        # Run Ipopt
+        data = json.dumps(
+            (config.problemfile,
+             config.solnfile,
+             options,
+             suffixes))
+        timelim = config.timelimit
+        if timelim:
+            timelim + min(max(1, 0.01 * self._timelim), 100)
+        cmd = [config.executable,
+        os.path.join(this_file_dir(), '_RUN.py')]
+        try:
+            rc, log = run(cmd, stdin=data, timelimit=timelim, tee=config.tee)
+        except WindowsError:
+            raise ApplicationError(
+                'Could not execute the command: %s\tError message: %s'
+                % (cmd, sys.exc_info()[1]))
+        sys.stdout.flush()
+
+        # Read in the results
+        result_data = None
+        with open(config.solnfile, 'r') as SOLN:
+            try:
+                result_data = json.load(SOLN)
+            except ValueError:
+                logger.error(
+                    "IpoptSolver_NL: no results data returned from the "
+                    "Ipopt subprocess.  Look at the solver log for more "
+                    "details (re-run with 'tee=True' to see the solver log.")
+                raise
+
+        results = SolverResults()
+        results.problem.update(result_data['problem'])
+        results.solver.update(result_data['solver'])
+        results.solver.name = 'gurobi_lp'
+
+        if not config.load_solution:
+            raise RuntimeError("TODO")
+        elif result_data['solution']['points']:
+            _sol = result_data['solution']['points'][0]
+            X = _sol['X']
+            for i, vname in enumerate(_sol['VarName']):
+                v = symbol_map.getObject(vname)
+                v.value = X[i]
+
+        return results
+
+
+IpoptSolver_NL.solve.__doc__ = add_docstring_list(IpoptSolver_NL.solve.__doc__, IpoptSolver.CONFIG)
+
+if __name__ == '__main__':
+    # Debugging
+    a = IpoptSolver_NL()
+    help(a.solve)