message: Fixed serial build
diff: @@ -8,8 +8,10 @@ namespace mfem
  class PowerMethod
  {
  - MPI_Comm comm;
  Vector v1;
  +#ifdef MFEM_USE_MPI
  + MPI_Comm comm;
  +#endif
  public:
  PowerMethod() {}
  @@ -35,7 +37,7 @@ class PowerMethod
  #ifdef MFEM_USE_MPI
  normV0 = InnerProduct(comm, v0, v0);
  -#elif
  +#else
  normV0 = InnerProduct(v0, v0);
  #endif
  @@ -45,7 +47,7 @@ class PowerMethod
  double eigenvalueNew;
  #ifdef MFEM_USE_MPI
  eigenvalueNew = InnerProduct(comm, v0, v1);
  -#elif
  +#else
  eigenvalueNew = InnerProduct(v0, v1);
  #endif
  double diff = std::abs((eigenvalueNew - eigenvalue) / eigenvalue);
  