Program compiles does not finish linking cannot resolve 'void dealii::SparseMatrix<double>::vmult<dealii::Vector<double> *snip*

[Matthew Rich]

Hi all,

Trucking through a problem and hit a snag with linking 

/home/mjrich/dealii/proj/proj.cc:294: error: undefined reference to 'void dealii::SparseMatrix<double>::vmult<dealii::Vector<double>, dealii::PackagedOperation<dealii::Vector<double> > >(dealii::Vector<double>&, dealii::PackagedOperation<dealii::Vector<double> > const&) const'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/proj.dir/build.make:294: proj] Error 1
make[1]: *** [CMakeFiles/Makefile2:291: CMakeFiles/proj.dir/all] Error 2
make: *** [Makefile:103: all] Error 2

the offending line 

 mass_matrix.vmult(system_rhs, -1*old_old_solution_u);

I am confused since I have it declared with 

        SparseMatrix<double> mass_matrix;

and 

        Vector<double> old_old_solution_u;

        Vector<double> system_rhs;

my list of includes are below. Why am I getting this error at the linking stage?

#include <deal.II/base/quadrature_lib.h>

#include <deal.II/base/function.h>

#include <deal.II/lac/vector.h>

#include <deal.II/lac/sparse_matrix.h>

#include <deal.II/lac/dynamic_sparsity_pattern.h>

#include <deal.II/lac/solver_cg.h>

#include <deal.II/lac/precondition.h>

#include <deal.II/lac/affine_constraints.h>

#include <deal.II/grid/tria.h>

#include <deal.II/grid/grid_generator.h>

#include <deal.II/grid/grid_tools.h>

#include <deal.II/dofs/dof_handler.h>

#include <deal.II/dofs/dof_tools.h>

#include <deal.II/fe/fe_q.h>

#include <deal.II/numerics/data_out.h>

#include <fstream>

#include <iostream>

#include <deal.II/numerics/vector_tools.h>

#include <deal.II/numerics/matrix_tools.h>

#include <deal.II/base/utilities.h>

#include <deal.II/fe/fe_q.h>

#include <deal.II/fe/fe_system.h>

#include <deal.II/lac/linear_operator_tools.h>

#include <deal.II/fe/mapping_q_generic.h>

#include <deal.II/lac/packaged_operation.h>

[Matthew Rich]

ok disregard this message. I found the error.