Behavior of each utility

Utility fourier

This utility is used as follows:

$ ${PATH}/fourier ${NAMELIST} ${GEOMETRY}

where ${PATH} is the path to the directory where the executable fourier exists, ${NAMELIST} is the NameList input-file name of {\mathcal H}\Phi/mVMC, and ${GEOMETRY} is the path to the Geometry file.

The behavior of this utility is slightly different between the correlation functions from each mode of {\mathcal H}\Phi (Lanczos, TPQ, Full diagonalization, LOBCG) and mVMC. In the following cases, we assume that CDataFileHead in the ModPara input file is "zvo" (default).

HPhi-Lanczos

In this case, HPhi writes correlation functions to the files zvo_cisajs.dat (one body) and zvo_cisajscktalt.dat (two body) in output/ directory. fourier utility reads this files, performs the Fourier transformation, and generate single file zvo_corr.dat in output/ directory.

HPhi-TPQ

HPhi writes correlation functions to files zvo_cisajs_run*step*.dat (one body), zvo_cisajscktalt_run*step*.dat (two body) at each trial and TPQ step to the output/ directory. fourier utility reads the one- and the two-body correlation function at each trial/TPQ-step, and performs Fourier transformation, and write to a file zvo_corr_run*step*.dat in output/ directory.

HPhi-Full diagonalization and LOBCG

HPhi writes correlation functions to files zvo_cisajs_eigen*.dat (one body) and zvo_cisajscktalt_eigen*.dat (two body) for each wavefunction to the output/ directory. fourier utility reads the one- and the two-body correlation function at each state and performs Fourier transformation, and write to a file zvo_corr_eigen*.dat in output/.

mVMC

vmc.out performs calculations according to the input parameters NDataIdxStart and NDataQtySmp in ModPara file, and it generates zvo_cisajs_???.dat (one body) and zvo_cisajscktalt_???.dat (two body) in output/ directory. fourier utility reads all of these files, performs Fourier transformation, computes the average

\begin{align}
\langle A \rangle = \frac{1}{N_{\rm Try}} \sum_{i=1}^{N_{\rm Try}} A_i
\end{align}

and the standard error

\begin{align}
\delta A = \frac{1}{N_{\rm Try} - 1}
\sqrt{\frac{1}{N_{\rm Try}} \sum_{i=1}^{N_{\rm Try}} (A_i - \langle A \rangle)^2}
\end{align}

of the real- and imaginary-part of each correlation function, and writes them to a file zvo_corr_eigen*.dat in output/ directory.

Utility corplot

This utility is used as follows:

$ ${PATH}/corplot ${CORR1} ${CORR2} ${CORR3} ...

where ${PATH} is the path to the directory which contains the executable corplot, ${CORR1}, ${CORR2}, ${CORR3}, ... are Correlation functions in the primitive Brillouin zone files generated by the utility fourier. Therefore, this utility can plot multiple files simultaneously (for example, to study the temperature dependence in the TPQ calculation).