Komega

[日本語]( README_ja.md#japanese ) / English

What ?

This package provides the solver library based on Shifted-Krylov subspace method and the software to calculate dynamical Green function by inputting the Hamiltonian and the vector of the excited state.

Download

• Latest release

  https://github.com/issp-center-dev/Komega/releases/download/v2.0.0/komega-2.0.0.tar.gz

• Release note

  https://github.com/issp-center-dev/Komega/releases/tag/v2.0.0

• Other version

  https://github.com/issp-center-dev/Komega/releases

Prerequisite

• fortran compiler
• BLAS library
• LAPACK library (Used in the sample program)
• MPI library (Optional)

Docments

• Manual for the Library
  • Japanese (HTML/PDF)
  • English (HTML/PDF)
• Manual for the sample program
  • Japanese (HTML/PDF)
  • English (HTML/PDF)

Directory Tree

• app/: The directory for the software
  • src/: The source directory for the software
  • sample/: The sample directory
    • Shiftk.nb: The mathmatica note book to test the software (for developers)
    • denovo/: Sample files not to input either Hamiltonian and the right-hand side initial vector
    • from_file/: Sample files to input both Hamiltonian and the right-hand side initial vector
• doc/: The documents directory (only japanese, english version will be provided from ver.1.0)
  • index.html : Top page for documents
  • library/: Directory for the document of the librariy
  • software/: Directory for the document of the sample program
• configure: Configuration script to build
• src/: The source directory for the libraries
• test/: The test directory for the libraries

Install

The simplest procedure is as follows:

• Type $ ./configure --prefix=install_dir; make; make install where install_dir should be replaced with the full path of the directory where the library will be stored.
• The following objects are generated in the directory specified by install_dir.
  • In install_dir/lib/: Static and shared libraries.
  • In install_dir/include/: Header file for C/C++.
  • install_dir/bin/Shiftk.out: Sample program

For more details, please see the manual.

Test of the software

• Change the directory to app/sample/denovo/ or app/sample/from_file/.
• Type the command $ install_dir/bin/ShiftK.out namelist.def.
• When the software works well, the files such as dynamicalG.dat will be generated.
• The details of the file format of namelist.def is written in the manual.

Usage of libraries

How to call each routines in the program

For fortran/C/C++

See the manual.

How to link the libraries

$ gfortran myprog.f90 -L install_dir/lib -lkomega -lblas -I install_dir/include
$ gcc myprog.c -L install_dir/lib -lkomega -lblas -I install_dir/include

etc.

Add the install_dir/lib directry to the environment variable LD_LIBRARY_PATH to execute the file with dynamic link.

Test for libraries(Optional)

• Move to the test/ directory.
• Type the command $ ./solve_cc.x < complex_freq.in.
• The program is normally finished when Residual vector becomes sufficiently small.
• You can check other programs (solve_rc.x, solve_cr.x, solve_rr.x) in a similar way. For solve_cr.x and solve_rr.x, please use real_freq.in` as an input file.
• The parameters in krylov.in(you can modify the file name freely) are as follows
  • ndim: The dimeinsion of the psuedo Hamiltonian
  • nl: This parameter is used to test the projection. The vectors are calculated from the target vector up to nl(<=ndim)th vector.
  • nz: The number of the frequences to calculate.
  • itermax: The maximum number of iterations.
  • threshold: The threshold to judge the convergence.
  • rnd_seed: The seed of random number to generate pseudo Hamiltonian.
  • Write the value of each frequencies line by line after this namelist.