f12jfc is a setup function in a suite of functions consisting of
f12jac,
f12jbc,
f12jfc,
f12jkc,
f12jsc,
f12jtc,
f12juc and
f12jvc. It is used to find some of the eigenvalues, and the corresponding eigenvectors, of a standard, generalized or polynomial eigenvalue problem. The initialization function
f12jac must have been called prior to calling
f12jfc. In addition calls to
f12jbc can be made to supply individual optional parameters to
f12jfc.
The suite of functions is suitable for the solution of large sparse eigenproblems where only a few eigenvalues from a selected range of the spectrum are required.
f12jfc is used to specify a circle or ellipse in the complex plane within which eigenvalues will be sought. By default, a circle centred at
$\mathit{emid}$ with a radius of
$r$ is created. Optionally,
f12jbc can be called prior to calling
f12jfc, using the optional parameters
${\mathbf{Ellipse\; Contour\; Ratio}}$ and
${\mathbf{Ellipse\; Rotation\; Angle}}$ to change the eccentricity of the ellipse and the inclination angle of its axis.
f12jfc uses these details to define nodes and weights for the elliptical contour, to be used by the solvers
f12jkc,
f12jsc,
f12jtc,
f12juc or
f12jvc.
For details of the other options available and how to set them see
Section 11.1 in
f12jbc.
Polizzi E (2009) Density-Matrix-Based Algorithms for Solving Eigenvalue Problems Phys. Rev. B. 79 115112
Not applicable.
Parts of the code for
f12jfc are distributed under the BSD software License. Please refer to
Library Licensors for further details.