changed: facilitate reuse of ForceBase derived integrands

previously there was no way to clear the buffers used during
integration. now initBuffer resizes only if necessary, but
always zeros the underlying buffer

src/ASM/IntegrandBase.C

@@ -571,26 +571,36 @@ bool NormBase::reducedInt (LocalIntegral& elmInt,
 
 ForceBase::~ForceBase ()
 {
-  for (LocalIntegral* lint : eForce)
-    delete lint;
-  delete[] eBuffer;
+  this->clearBuffer();
 }
 
 
-bool ForceBase::initBuffer (size_t nel)
+void ForceBase::clearBuffer ()
 {
-  if (eBuffer) return false;
+  for (LocalIntegral* lint : eForce)
+    delete lint;
+  eForce.clear();
+  delete[] eBuffer;
+  eBuffer = nullptr;
+}
 
+
+void ForceBase::initBuffer (size_t nel)
+{
   size_t ncmp = this->getNoComps();
+
+  if (eForce.size() != nel) {
+    this->clearBuffer();
+
     eBuffer = new double[ncmp*nel];
-  memset(eBuffer,0,ncmp*nel*sizeof(double));
 
     eForce.reserve(nel);
     double* q = eBuffer;
     for (size_t i = 0; i < nel; i++, q += ncmp)
       eForce.push_back(new ElmNorm(q,ncmp));
+  }
 
-  return true;
+  memset(eBuffer,0,ncmp*nel*sizeof(double));
 }
 
 

src/ASM/IntegrandBase.h

@@ -481,7 +481,7 @@ public:
   virtual ~ForceBase();
 
   //! \brief Allocates internal element force buffers.
-  bool initBuffer(size_t nel);
+  void initBuffer(size_t nel);
 
   //! \brief Assembles the global forces.
   void assemble(RealArray& force) const;
@@ -536,6 +536,9 @@ public:
   virtual bool hasBoundaryTerms() const { return true; }
 
 protected:
+  //! \brief Clears out internal buffers.
+  void clearBuffer();
+
   IntegrandBase& myProblem; //!< The problem-specific data
   LintegralVec      eForce; //!< Local integrals used during force integration
   double*          eBuffer; //!< Element force buffer used during integration