Hi,
I could figure out how to give Identity Matrix instead of the mass matrix
to solve the Standard Eigen value problem. However, on running, I am
getting the folllowing error.
Timestep 1 @ 0.1s
_______________________________________________________________________________________
SOLVER STEP | LIN_IT LIN_RES RES_NORM RES_U
NU_NORM NU_U
_______________________________________________________________________________________
0 CST ASM SLV CMakeFiles/run.dir/build.make:57: recipe for target
'CMakeFiles/run' failed
make[3]: *** [CMakeFiles/run] Segmentation fault (core dumped)
CMakeFiles/Makefile2:131: recipe for target 'CMakeFiles/run.dir/all' failed
make[2]: *** [CMakeFiles/run.dir/all] Error 2
CMakeFiles/Makefile2:138: recipe for target 'CMakeFiles/run.dir/rule' failed
make[1]: *** [CMakeFiles/run.dir/rule] Error 2
Makefile:144: recipe for target 'run' failed
make: *** [run] Error 2
I am copying here the solve_linear_system function and the part that I
updated is blue in color. Also, I wish to calculate the eigenvalues after
the newton method has converged. I am a bit confused of where actually to
solve the standard eigenvalue problem in the code for my purpose. Could
someone please help me with these questions?
------------------------------------------------
template <int dim,typename NumberType>
std::pair<unsigned int, double>
Solid<dim,NumberType>::solve_linear_system(BlockVector<double>
&newton_update)
{
BlockVector<double> A(dofs_per_block);
BlockVector<double> B(dofs_per_block);
unsigned int lin_it = 0;
double lin_res = 0.0;
{
timer.enter_subsection("Linear solver");
std::cout << " SLV " << std::flush;
if (parameters.type_lin == "CG")
{
const int solver_its = static_cast<unsigned int>(
tangent_matrix.block(u_dof, u_dof).m()
* parameters.max_iterations_lin);
const double tol_sol = parameters.tol_lin
* system_rhs.block(u_dof).l2_norm();
SolverControl solver_control(solver_its, tol_sol);
GrowingVectorMemory<Vector<double> > GVM;
SolverCG<Vector<double> > solver_CG(solver_control, GVM);
PreconditionSelector<SparseMatrix<double>, Vector<double> >
preconditioner (parameters.preconditioner_type,
parameters.preconditioner_relaxation);
preconditioner.use_matrix(tangent_matrix.block(u_dof, u_dof));
solver_CG.solve(tangent_matrix.block(u_dof, u_dof),
newton_update.block(u_dof),
system_rhs.block(u_dof),
preconditioner);
lin_it = solver_control.last_step();
lin_res = solver_control.last_value();
}
else if (parameters.type_lin == "Direct")
{
SparseDirectUMFPACK A_direct;
A_direct.initialize(tangent_matrix.block(u_dof, u_dof));
A_direct.vmult(newton_update.block(u_dof),
system_rhs.block(u_dof));
lin_it = 1;
lin_res = 0.0;
}
else
Assert (false, ExcMessage("Linear solver type not implemented"));
std::vector<std::complex<double>> eigenvalues;
std::vector<Vector<double> > eigenvectors;
SparseDirectUMFPACK inverse;
inverse.initialize (tangent_matrix.block(u_dof,u_dof));
SolverControl solver_control(1000, 1e-9);
ArpackSolver eigensolver(solver_control,
ArpackSolver::AdditionalData(ArpackSolver::WhichEigenvalues::algebraically_smallest));
eigensolver.solve(tangent_matrix.block(u_dof,u_dof), IdentityMatrix(),
inverse, eigenvalues, eigenvectors,eigenvalues.size());
timer.leave_subsection();
}
---------------------------------------------
On Friday, September 25, 2020 at 12:15:29 AM UTC+5:30 Animesh Rastogi IIT
Gandhinagar wrote:
> I could finally configure dealii using ARPACK. I am facing issues in
> initialising the identity matrix that is to be given to the
> eigensolver.solve(). I am trying to replace the mass matrix with an
> identity matrix..
>
> I am copying the code again in this thread..
>
> std::vector<std::complex<double>> eigenvalues;
> std::vector<Vector<double> > eigenvectors;
> SparseMatrix<double> identity (IdentityMatrix(u_dof));
> SparseDirectUMFPACK inverse;
> inverse.initialize (tangent_matrix.block(u_dof,u_dof));
> const int eigensolver_its = static_cast<unsigned int>(
> tangent_matrix.block(u_dof, u_dof).m()
> * parameters.max_iterations_lin);
> SolverControl solver_control(eigensolver_its, 1e-9);
> ArpackSolver::ArpackSolver eigensolver(solver_control);
> eigensolver.solve(tangent_matrix.block(u_dof,u_dof), identity,
> inverse, eigenvalues, eigenvectors);
>
> I am getting the following error for this -
>
> error: request for member ‘vmult’ in ‘mass_matrix’, which is of non-class
> type ‘dealii::BlockSparseMatrix<double>(dealii::IdentityMatrix)’
> mass_matrix.vmult(tmp, src);
>
> Could someone please help me with this?
>
> Thanks!
>
> Animesh
> On Thursday, September 24, 2020 at 4:40:47 PM UTC+5:30 Animesh Rastogi IIT
> Gandhinagar wrote:
>
>> Hi Jean,
>>
>> It turns out that I did not configure dealii with ARPACK. So I followed
>> the readme instructions and installed and compiled ARPACK as suggested. I
>> also tried to run the examples in the ARPACK directory and they are running
>> without any errors. However, when I tried to reconfigure deallii using the
>> selfcompiled version, it says the following error.
>>
>> Could not find the arpack library!
>>
>> Please ensure that a suitable arpack library is installed on your
>> computer.
>>
>> If the library is not at a default location, either provide some hints
>> for
>> autodetection,
>>
>> $ ARPACK_DIR="..." cmake <...>
>> $ cmake -DARPACK_DIR="..." <...>
>>
>> or set the relevant variables by hand in ccmake.
>>
>> I used the following cmake command to configure dealii again -
>>
>> cmake -DDEAL_II_WITH_PETSC=ON
>> -DPETSC_DIR=/home/animesh/Documents/petsc-3.13.5
>> -DPETSC_ARCH=arch-linux-c-debug -DDEAL_II_WITH_METIS=ON
>> -DDEAL_II_WITH_MPI=ON -DDEAL_II_WITH_ARPACK=ON
>> -DARPACK_DIR=/home/animesh/Documents/ARPACK ..
>>
>> I checked that the path of the directory of ARPACK that I am giving here
>> is correct.
>>
>> I followed the instructions in this page -
>> https://www.dealii.org/current/external-libs/arpack.html.
>> Also, I couldn't figure out what it means when it says "For compilation
>> of ARPACK we emphasize adding the compiler flag -fPIC". What is -fPIC
>> and where should I use this flag?
>>
>> Could you please help me with this and the question about identity matrix
>> asked in the previous mail of this thread?
>>
>> Thanks a lot!
>>
>> Animesh
>> On Thursday, September 24, 2020 at 11:56:24 AM UTC+5:30 Animesh Rastogi
>> IIT Gandhinagar wrote:
>>
>>> Hi Jean,
>>>
>>> Thanks a lot for your response. I am trying as you suggested. I have
>>> added the following code inside the linear solver so that I can get the
>>> eigenvalues at every newton step.
>>>
>>> std::vector<std::complex<double>> eigenvalues;
>>> std::vector<Vector<double> > eigenvectors;
>>> SparseMatrix<double> identity (IdentityMatrix(u_dof));
>>> SparseDirectUMFPACK inverse;
>>> inverse.initialize (tangent_matrix.block(u_dof,u_dof));
>>> const int eigensolver_its = static_cast<unsigned int>(
>>> tangent_matrix.block(u_dof, u_dof).m()
>>> * parameters.max_iterations_lin);
>>> SolverControl solver_control(eigensolver_its, 1e-9);
>>> ArpackSolver::ArpackSolver eigensolver(solver_control);
>>> eigensolver.solve(tangent_matrix.block(u_dof,u_dof), identity,
>>> inverse, eigenvalues, eigenvectors);
>>>
>>> However, I am getting the follwing error while compiling.
>>>
>>> error: ‘ArpackSolver’ has not been declared
>>>
>>> I have included the header file #include <deal.II/lac/arpack_solver.h>.
>>>
>>> Also, could you please let me know if I have declared the identity
>>> matrix correctly? I am replacing the mass matrix B with the Identity matrix
>>> to compute the eigenvalues and eigenvectors.
>>>
>>> Thanks!
>>>
>>> Animesh
>>> On Thursday, September 24, 2020 at 1:10:35 AM UTC+5:30 Jean-Paul
>>> Pelteret wrote:
>>>
>>>> Hi Animesh,
>>>>
>>>> Although in that code-gallery example the system is assembled into a
>>>> BlockSparseMatrix<double>, the system actually has only one block. So you
>>>> can retrieve the underlying SparseMatrix<double> (and Vector<double> for
>>>> the RHS) via
>>>> tangent_matrix.block(u_dof, u_dof);
>>>> system_rhs.block(u_dof);
>>>> and use them with one of the standard eigensolvers (maybe ArpackSolver
>>>> <https://dealii.org/developer/doxygen/deal.II/classArpackSolver.html>,
>>>> since you want both the eigenvalues and eigenvectors).
>>>>
>>>> I hope that this helps you!
>>>>
>>>> Best,
>>>> Jean-Paul
>>>>
>>>> On 23 Sep 2020, at 20:53, Animesh Rastogi IIT Gandhinagar <
>>>> animesh...@alumni.iitgn.ac.in> wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I am trying to play with the code of Quassi Static Finite Strain
>>>> Compressibility
>>>> <https://dealii.org/developer/doxygen/deal.II/code_gallery_Quasi_static_Finite_strain_Compressible_Elasticity.html>.
>>>>
>>>> I want to calculate the eigenvalues and eigenvectors of the System Tangent
>>>> Matrix (BlockSparseMatrix<double>
>>>> <https://dealii.org/developer/doxygen/deal.II/classBlockSparseMatrix.html>
>>>> tangent_matrix) that we get at every time step after the Newton method has
>>>> converged. However, I could not find any function to calculate the
>>>> eigenvalues and eigenvectors of the BlockSparse Matrix. Could someone
>>>> please help me with this?
>>>>
>>>> Thanks!
>>>>
>>>> AR
>>>>
>>>> --
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>>>>
>>>>
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