How to copy a SoPlex model?

Question

I am using SoPlex to set up a lp and solve it. I then try to make a copy of the original lp and modify it. My code looks like this:

int main()
{
   using namespase soplex;
   SoPlex spx;
   // add columns
   // add rows
   auto status = spx.optimize();

   SoPlex copy(spx);
   // modify some columns

   status = copy.optimize();

   return 0;
}

When I run my code in valgrind, I notice that memory allocated by methods inside the SoPlex copy constructor are not freed.

Is there a memory leak inside SoPlex or am I not using it correctly?

Answer 1

You are using the copy functionality correctly. There is indeed a memory leak in SoPlex that is going to be fixed in the next version.

In the meantime you could try to apply this patch for SoPlex-4.0.1:

diff --git a/src/soplex/slufactor.cpp b/src/soplex/slufactor.cpp
index ae41604..a3314d8 100644
--- a/src/soplex/slufactor.cpp
+++ b/src/soplex/slufactor.cpp
@@ -1230,8 +1230,6 @@ SLUFactor::SLUFactor(const SLUFactor& old)
    l.rperm     = 0;

    solveCount = 0;
-   solveTime = TimerFactory::createTimer(timerType);
-   factorTime = TimerFactory::createTimer(timerType);

    try
    {
@@ -1326,16 +1324,23 @@ void SLUFactor::freeAll()

    if(l.rperm)
       spx_free(l.rperm);
+
+   if(solveTime)
+   {
+      solveTime->~Timer();
+      spx_free(solveTime);
+   }
+
+   if(factorTime)
+   {
+      factorTime->~Timer();
+      spx_free(factorTime);
+   }
 }

 SLUFactor::~SLUFactor()
 {
    freeAll();
-
-   solveTime->~Timer();
-   factorTime->~Timer();
-   spx_free(solveTime);
-   spx_free(factorTime);
 }

 static Real betterThreshold(Real th)
diff --git a/src/soplex/spxbasis.cpp b/src/soplex/spxbasis.cpp
index 6370e89..40d201b 100644
--- a/src/soplex/spxbasis.cpp
+++ b/src/soplex/spxbasis.cpp
@@ -1363,6 +1363,7 @@ SPxBasis::~SPxBasis()
       factor = 0;
    }

+   theTime->~Timer();
    spx_free(theTime);
 }