Overview

This document is a manual for \(K\omega\) which is the library to solve the shifted linear equation within the Krylov subspace. This library provides routines to solve the following shifted linear equation (with the projection),

\[\begin{align} G_{i j}(z) = \langle i | (z {\hat I} -{\hat H})^{-1}| j \rangle \equiv {\boldsymbol \varphi}_i^{*} \cdot (z{\hat I}-{\hat H})^{-1} {\boldsymbol \varphi}_j. \end{align}\]

The source codes of \(K\omega\) is written in FORTRAN and requires the BLAS Level 1 routines.