LapH_EigSys

Serial version of the eigensystem calculation in the stochastic Laplacian Heaviside Smearing

Dependencies:

• c-lime by USQCD
• Eigen
• PETSc by the Argonne National Laboratory
• SLEPc an extension to PETSc under maintenance of the Univeristat Politecnica de Valencia

Preparations

A PETSc example configure script can be found in install/conf_scripts. For the package to work complex scalars, lapack and blas are needed. The C language should be C++ and the g++ compiler and linker should be of version later than 4.6.

Compiling:

Once the dependencies are built the Makefile in ./src can be invoked to compile the executable ev_ts. The include of mpiuni avoids certain issues with PETSc looking for mpi headers which are not needed. Cleaning up works by calling the target

make myclean

Execution:

For execution make sure parameters.txt is adjusted accordingly and gauge configurations are at hand. Normal execution is done by invoking

./ev_ts =CONF=

where =CONF= should be a valid configuration number. The according parameters.txt is read from the execution directory. The program output contains small sanity checks as the $\tr(V^dag * V}$ that should equal the number of eigenvectors. Eigenvectors, eigenvalues and phases are saved in binary format where the eigenvectors are phase fixed.

MPI Compatibility:

It is now possible to use a version parallelized with MPI. Therefore PETSc and SLEPc have to be compiled with MPI-Support. In the programm itself every rank has an own EPS-Instance, ensured via the usage of PETSC_COMM_SELF instead of PETSC_COMM_WORLD. At the moment the ranks play as well the role of choosing the time slice, therefore MPI_Size() has to be the time extent of the lattice.