make explicit inits for all solvers with standard interface. (#326)

* make explicit inits for all solvers with standard interface.

* new changes to apis. Took out warmStart from the core object and into optionsDict.

* bump version

* fixes #280

Author: pchtsp

HISTORY

@@ -1,6 +1,31 @@
 # PuLP, Copyright J.S. Roy ([email protected]), 2002-2005
 #       Copyright S.A.Mitchell ([email protected]), 2007-
+#       Copyright F.Peschiera ([email protected]), 2019-
 # See the LICENSE file for copyright information.
+2.3 2020-08-04
+    Added plugin page in docs
+    Standardize arguments of solvers to appear in docs
+    Fixes to import and export of LpProblem and solver
+    Added warm start to GUROBI
+2.2 2020-04-06
+    Contribution files
+    Standard arguments: logPath, gapRel, gapAbs.
+    Import and export solver objects
+    Import and export LpProblem
+    Took out amply to its own package
+    Standard tmp file handling in _CMD solvers
+    Refactored writeMPS    
+2.1 2020-04-06
+    Added MOSEK solver
+    New documentation
+    Put tests inside package
+    Added warm start to CPLEX_PY
+2.0 2019-11-23
+    Restructured solvers code
+    Added unittests package
+    Added CHOCO solver
+    Added warm start for CBC_CMD, GUROBI_CMD, CPLEX_CMD
+    Automated deploy
 1.6.1, 2015-12-25
     Fix for dummy variables
 1.5.4, 2013-03-18

ROADMAP

@@ -34,6 +34,18 @@ class CHOCO_CMD(LpSolver_CMD):
     """The CHOCO_CMD solver"""
     name = 'CHOCO_CMD'
 
+    def __init__(self, path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None):
+        """
+        :param bool mip: if False, assume LP even if integer variables
+        :param bool msg: if False, no log is shown
+        :param float timeLimit: maximum time for solver (in seconds)
+        :param list options: list of additional options to pass to solver
+        :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving
+        :param str path: path to the solver binary
+        """
+        LpSolver_CMD.__init__(self, mip=mip, msg=msg, timeLimit=timeLimit,
+                              options=options, path=path, keepFiles=keepFiles)
+
     def defaultPath(self):
         return self.executableExtension("choco-parsers-with-dependencies.jar")
 
@@ -146,11 +158,9 @@ def actualSolve(self, lp, callback=None):
             """Solve a well formulated lp problem"""
             raise PulpSolverError("PULP_CHOCO_CMD: Not Available (check permissions on %s)" % self.pulp_choco_path)
     else:
-        def __init__(self, path=None, *args, **kwargs):
-            """
-            just loads up CHOCO_CMD with the path set
-            """
+        def __init__(self, path=None, keepFiles=0, mip=True, msg=True, options=None, timeLimit=None):
             if path is not None:
                 raise PulpSolverError('Use CHOCO_CMD if you want to set a path')
             # check that the file is executable
-            CHOCO_CMD.__init__(self, path=self.pulp_choco_path, *args, **kwargs)
+            CHOCO_CMD.__init__(self, path=self.pulp_choco_path, keepFiles=keepFiles,
+                               mip=mip, msg=msg, options=options, timeLimit=timeLimit)

pulp/apis/choco_api.py

@@ -42,27 +42,53 @@ class COIN_CMD(LpSolver_CMD):
     def defaultPath(self):
         return self.executableExtension(cbc_path)
 
-    def __init__(self, fracGap = None, maxSeconds = None, *args, **kwargs):
+    def __init__(self, mip=True, msg=True, timeLimit=None,
+                 fracGap=None, maxSeconds=None, gapRel=None, gapAbs=None,
+                 presolve=None, cuts=None, strong=None, options=None,
+                 warmStart=False, keepFiles=False, path=None, threads=None,
+                 logPath=None, mip_start=False):
         """
-        :param fracGap:
-        :param maxSeconds:
-        :param args:
-        :param kwargs: includes presolve, cuts, strong
+        :param bool mip: if False, assume LP even if integer variables
+        :param bool msg: if False, no log is shown
+        :param float timeLimit: maximum time for solver (in seconds)
+        :param float gapRel: relative gap tolerance for the solver to stop (in fraction)
+        :param float gapAbs: absolute gap tolerance for the solver to stop
+        :param int threads: sets the maximum number of threads
+        :param list options: list of additional options to pass to solver
+        :param bool warmStart: if True, the solver will use the current value of variables as a start
+        :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving
+        :param str path: path to the solver binary
+        :param str logPath: path to the log file
+        :param bool presolve: if True, adds presolve on
+        :param bool cuts: if True, adds gomory on knapsack on probing on
+        :param bool strong: if True, adds strong
+        :param float fracGap: deprecated for gapRel
+        :param float maxSeconds: deprecated for timeLimit
+        :param bool mip_start: deprecated for warmStart
         """
 
-        if fracGap:
-            warnings.warn("Parameter fracGap is being depreciated for standard 'gapRel'")
-            if 'gapRel' in kwargs:
-                warnings.warn("Parameter kwargs and fracGap passed, using kwargs")
+        if fracGap is not None:
+            warnings.warn("Parameter fracGap is being depreciated for gapRel")
+            if gapRel is not None:
+                warnings.warn("Parameter gapRel and fracGap passed, using gapRel")
             else:
-                kwargs['gapRel'] = fracGap
-        LpSolver_CMD.__init__(self, *args, **kwargs)
-        if maxSeconds:
-            warnings.warn("Parameter maxSeconds is being depreciated for standard 'timeLimit'")
-            if self.timeLimit:
-                warnings.warn("Parameter timeLimit and maxSeconds passed, using timeLimit ")
+                gapRel = fracGap
+        if maxSeconds is not None:
+            warnings.warn("Parameter maxSeconds is being depreciated for timeLimit")
+            if timeLimit is not None:
+                warnings.warn("Parameter timeLimit and maxSeconds passed, using timeLimit")
             else:
-                self.timeLimit = maxSeconds
+                timeLimit = maxSeconds
+        if mip_start:
+            warnings.warn("Parameter mip_start is being depreciated for warmStart")
+            if warmStart:
+                warnings.warn("Parameter mipStart and mip_start passed, using warmStart")
+            else:
+                warmStart = mip_start
+        LpSolver_CMD.__init__(self, gapRel=gapRel, mip=mip, msg=msg, timeLimit=timeLimit,
+                              presolve=presolve, cuts=cuts, strong=strong, options=options,
+                              warmStart=warmStart, path=path, keepFiles=keepFiles,
+                              threads=threads, gapAbs=gapAbs, logPath=logPath)
 
     def copy(self):
         """Make a copy of self"""
@@ -96,7 +122,7 @@ def solve_CBC(self, lp, use_mps=True):
             constraintsNames = dict((c, c) for c in lp.constraints)
             objectiveName = None
             cmds = ' ' + tmpLp + " "
-        if self.warmStart:
+        if self.optionsDict.get('warmStart', False):
             self.writesol(tmpMst, lp, vs, variablesNames, constraintsNames)
             cmds += 'mips {} '.format(tmpMst)
         if self.timeLimit is not None:
@@ -114,7 +140,8 @@ def solve_CBC(self, lp, use_mps=True):
             pipe = None
         else:
             pipe = open(os.devnull, 'w')
-        if 'logPath' in self.optionsDict:
+        logPath = self.optionsDict.get('logPath')
+        if logPath:
             if self.msg:
                 warnings.warn('`logPath` argument replaces `msg=1`. The output will be redirected to the log file.')
             pipe = open(self.optionsDict['logPath'], 'w')
@@ -258,14 +285,19 @@ def actualSolve(self, lp, callback = None):
             """Solve a well formulated lp problem"""
             raise PulpSolverError("PULP_CBC_CMD: Not Available (check permissions on %s)" % self.pulp_cbc_path)
     else:
-        def __init__(self, path=None, *args, **kwargs):
-            """
-            just loads up COIN_CMD with the path set
-            """
+        def __init__(self, mip=True, msg=True, timeLimit=None,
+                     fracGap=None, maxSeconds=None, gapRel=None, gapAbs=None,
+                     presolve=None, cuts=None, strong=None, options=None,
+                     warmStart=False, keepFiles=False, path=None, threads=None,
+                     logPath=None, mip_start=False):
             if path is not None:
                 raise PulpSolverError('Use COIN_CMD if you want to set a path')
             #check that the file is executable
-            COIN_CMD.__init__(self, path=self.pulp_cbc_path, *args, **kwargs)
+            COIN_CMD.__init__(self, path=self.pulp_cbc_path, mip=mip, msg=msg, timeLimit=timeLimit,
+                              fracGap=fracGap, maxSeconds=maxSeconds, gapRel=gapRel, gapAbs=gapAbs,
+                              presolve=presolve, cuts=cuts, strong=strong, options=options,
+                              warmStart=warmStart, keepFiles=keepFiles, threads=threads,
+                              logPath=logPath, mip_start=mip_start)
 
 
 def COINMP_DLL_load_dll(path):

pulp/apis/coin_api.py

@@ -173,32 +173,22 @@ class LpSolver:
     """A generic LP Solver"""
     name = 'LpSolver'
 
-    def __init__(self, mip = True, msg = True, options = None, mip_start=False, timeLimit=None,
-                 warmStart=False, *args, **kwargs):
+    def __init__(self, mip=True, msg=True, options=None, timeLimit=None,
+                 *args, **kwargs):
         """
-
-        :param bool mip: if False, assume LP even if integer variables.
-        :param bool msg: if False, no log is shown.
+        :param bool mip: if False, assume LP even if integer variables
+        :param bool msg: if False, no log is shown
         :param list options:
-        :param bool warmStart:
-        :param float timeLimit: maximum time for solver
+        :param float timeLimit: maximum time for solver (in seconds)
         :param args:
         :param kwargs: optional named options to pass to each solver,
                         e.g. gapRel=0.1, gapAbs=10, logPath="",
-
         """
         if options is None:
             options = []
         self.mip = mip
         self.msg = msg
         self.options = options
-        self.warmStart = warmStart
-        if mip_start:
-            warnings.warn("Parameter mip_start is being depreciated for standard 'warmStart'")
-            if warmStart:
-                warnings.warn("Parameter mipStart and mip_start passed, using warmStart")
-            else:
-                self.warmStart = mip_start
         self.timeLimit = timeLimit
 
         # here we will store all other relevant information including:
@@ -330,11 +320,17 @@ def getCplexStyleArrays(self,lp, senseDict=None, LpVarCategories=None, LpObjSens
 
     def to_dict(self):
         data = dict(solver=self.name)
-        translate = {}
-        for v in ['mip', 'msg', 'warmStart', 'timeLimit', 'options', 'keepFiles']:
-            k = translate.get(v, v)
+        for k in ['mip', 'msg', 'keepFiles']:
+            try:
+                data[k] = getattr(self, k)
+            except AttributeError:
+                pass
+        for k in ['timeLimit', 'options']:
+            # with these ones, we only export if it has some content:
             try:
-                data[k] = getattr(self, v)
+                value = getattr(self, k)
+                if value:
+                    data[k] = value
             except AttributeError:
                 pass
         data.update(self.optionsDict)
@@ -350,9 +346,13 @@ class LpSolver_CMD(LpSolver):
 
     name = 'LpSolver_CMD'
 
-    def __init__(self, path=None, keepFiles=0, *args, **kwargs):
+    def __init__(self, path=None, keepFiles=False, *args, **kwargs):
         """
 
+        :param bool mip: if False, assume LP even if integer variables
+        :param bool msg: if False, no log is shown
+        :param list options: list of additional options to pass to solver (format depends on the solver)
+        :param float timeLimit: maximum time for solver (in seconds)
         :param str path: a path to the solver binary
         :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving
         :param args: parameters to pass to :py:class:`LpSolver`