From f7dc28152ebe001c56c37d2e6898ac67135f924c Mon Sep 17 00:00:00 2001
From: Stuart Mitchell <hg@stuartmitchell.com>
Date: Thu, 7 Jun 2012 20:32:28 +1200
Subject: [PATCH] added dual information to cbc

---
 src/pulp/pulp.py    |  9 +++++++--
 src/pulp/solvers.py | 43 ++++++++++++++++++++++++++++++++++++-------
 src/pulp/tests.py   |  2 +-
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/src/pulp/pulp.py b/src/pulp/pulp.py
index 7b2e5c0..9ba9afb 100755
--- a/src/pulp/pulp.py
+++ b/src/pulp/pulp.py
@@ -1553,9 +1553,14 @@ class LpProblem(object):
         for name in values:
             self.constraints[name].pi = values[name]
 
-    def assignConsSlack(self, values):
+    def assignConsSlack(self, values, activity=False):
         for name in values:
-            self.constraints[name].slack = float(values[name])
+            if activity:
+                #reports the activitynot the slack
+                self.constraints[name].slack = -1 * (
+                        self.constraints[name].constant + float(values[name]))
+            else:
+                self.constraints[name].slack = float(values[name])
 
     def get_dummyVar(self):
         if self.dummyVar is None:
diff --git a/src/pulp/solvers.py b/src/pulp/solvers.py
index e242afe..519f1ff 100644
--- a/src/pulp/solvers.py
+++ b/src/pulp/solvers.py
@@ -1274,6 +1274,8 @@ class COIN_CMD(LpSolver_CMD):
             cmds += "branch "
         else:
             cmds += "initialSolve "
+        if lp.isMIP:
+            cmds += "printingOptions rows "
         cmds += "solution "+tmpSol+" "
         if self.msg:
             pipe = None
@@ -1288,11 +1290,16 @@ class COIN_CMD(LpSolver_CMD):
         if not os.path.exists(tmpSol):
             raise PulpSolverError, "Pulp: Error while executing "+self.path
         if use_mps:
-            lp.status, values = self.readsol_MPS(tmpSol, lp, lp.variables(),
+            lp.status, values, reducedCosts, shadowPrices, slacks = self.readsol_MPS(
+                        tmpSol, lp, lp.variables(),
                         variablesNames, constraintsNames, objectiveName)
         else:
-            lp.status, values = self.readsol_LP(tmpSol, lp, lp.variables())
+            lp.status, values, reducedCosts, shadowPrices, slacks = self.readsol_LP(
+                    tmpSol, lp, lp.variables())
         lp.assignVarsVals(values)
+        lp.assignVarsDj(reducedCosts)
+        lp.assignConsPi(shadowPrices)
+        lp.assignConsSlack(slacks, activity=True)
         if not self.keepFiles:
             try:
                 os.remove(tmpLp)
@@ -1312,12 +1319,19 @@ class COIN_CMD(LpSolver_CMD):
         values = {}
 
         reverseVn = {}
-        for k,n in variablesNames.iteritems():
+        for k, n in variablesNames.iteritems():
             reverseVn[n] = k
+        reverseCn = {}
+        for k, n in constraintsNames.iteritems():
+            reverseCn[n] = k
+
 
         for v in vs:
             values[v.name] = 0.0
 
+        reducedCosts = {}
+        shadowPrices = {}
+        slacks = {}
         cbcStatus = {'Optimal': LpStatusOptimal,
                     'Infeasible': LpStatusInfeasible,
                     'Unbounded': LpStatusUnbounded,
@@ -1330,15 +1344,24 @@ class COIN_CMD(LpSolver_CMD):
                 break
             l = l.split()
             vn = l[1]
+            val = l[2]
+            dj = l[3]
             if vn in reverseVn:
-                values[reverseVn[vn]] = float(l[2])
-        return status, values
+                values[reverseVn[vn]] = float(val)
+                reducedCosts[reverseVn[vn]] = float(dj)
+            if vn in reverseCn:
+                slacks[reverseCn[vn]] = float(val)
+                shadowPrices[reverseCn[vn]] = float(dj)
+        return status, values, reducedCosts, shadowPrices, slacks
 
     def readsol_LP(self, filename, lp, vs):
         """
         Read a CBC solution file generated from an lp (good names)
         """
         values = {}
+        reducedCosts = {}
+        shadowPrices = {}
+        slacks = {}
         for v in vs:
             values[v.name] = 0.0
         cbcStatus = {'Optimal': LpStatusOptimal,
@@ -1353,9 +1376,15 @@ class COIN_CMD(LpSolver_CMD):
                 break
             l = l.split()
             vn = l[1]
+            val = l[2]
+            dj = l[3]
             if vn in values:
-                values[vn] = float(l[2])
-        return status, values
+                values[vn] = float(val)
+                reducedCosts[vn] = float(dj)
+            if vn in lp.constraints:
+                slacks[vn] = float(val)
+                shadowPrices[vn] = float(dj)
+        return status, values, reducedCosts, shadowPrices, slacks
 
 COIN = COIN_CMD
 
diff --git a/src/pulp/tests.py b/src/pulp/tests.py
index 5a786ad..bb56126 100644
--- a/src/pulp/tests.py
+++ b/src/pulp/tests.py
@@ -378,7 +378,7 @@ def pulpTest080(solver):
     prob += c2,"c2"
     prob += c3,"c3"
 
-    if solver.__class__ in [CPLEX_DLL, CPLEX_CMD, COINMP_DLL]:
+    if solver.__class__ in [CPLEX_DLL, CPLEX_CMD, COINMP_DLL, PULP_CBC_CMD]:
         print "\t Testing dual variables and slacks reporting"
         pulpTestCheck(prob, solver, [LpStatusOptimal],
                   sol = {x:4, y:-1, z:6},