track assembled state in petsc

use this to fix direct solve for preassembled sparsematrix

src/LinAlg/PETScMatrix.C

@@ -150,6 +150,7 @@ PETScMatrix::PETScMatrix (const ProcessAdm& padm, const LinSolParams& spar)
   setParams = true;
   ISsize = 0;
   nLinSolves = 0;
+  assembled = false;
 }
 
 
@@ -432,6 +433,8 @@ void PETScMatrix::initAssembly (const SAM& sam, bool delayLocking)
       MatSetOption(it,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
  #endif
   }
+
+  assembled = false;
 }
 
 
@@ -464,6 +467,8 @@ bool PETScMatrix::endAssembly()
 {
   // Finalizes parallel assembly process
   MatAssemblyEnd(pA,MAT_FINAL_ASSEMBLY);
+  assembled = true;
+
   return true;
 }
 
@@ -479,6 +484,8 @@ void PETScMatrix::init ()
     for (auto& it : matvec)
       MatZeroEntries(it);
   }
+
+  assembled = false;
 }
 
 
@@ -501,7 +508,7 @@ bool PETScMatrix::solve (SystemVector& B, bool newLHS, Real*)
   if (!Bptr)
     return false;
 
-  if (A.empty())
+  if (A.empty() || !assembled)
     return this->solveDirect(*Bptr);
 
   Vec x;
@@ -579,7 +586,7 @@ bool PETScMatrix::solveDirect(PETScVector& B)
 {
   // the sparsity pattern has been grown in-place, we need to init PETsc state.
   // this is currently only used for patch-global L2 systems.
-  if (!this->optimiseSLU())
+  if (A.empty() && !this->optimiseSLU())
     return false;
 
   // Set correct number of rows and columns for matrix.

src/LinAlg/PETScMatrix.h

@@ -198,6 +198,7 @@ protected:
   PetscRealVec        coords;          //!< Coordinates of local nodes (x0,y0,z0,x1,y1,...)
   ISMat               dirIndexSet;     //!< Direction ordering
   int                 nLinSolves;      //!< Number of linear solves
+  bool                assembled;       //!< True if PETSc matrix has been assembled
 
   IS glob2LocEq = nullptr; //!< Index set for global-to-local equations.
   std::vector<Mat> matvec; //!< Blocks for block matrices.