Extended Eigensolver Naming Conventions

There are two different types of interfaces available in the Extended Eigensolver routines:

1. The reverse communication interfaces (RCI):

   ?feast_<matrix type>_rci

   These interfaces are matrix free format (the interfaces are independent of the matrix data formats). You must provide matrix-vector multiply and direct/iterative linear system solvers for your own explicit or implicit data format.

2. The predefined interfaces:

   ?feast_<matrix type><type of eigenvalue problem>

   are predefined drivers for ?feast reverse communication interface that act on commonly used matrix data storage (dense, banded and compressed sparse row representation), using internal matrix-vector routines and selected inner linear system solvers.

For these interfaces:

• ? indicates the data type of matrix A (and matrix B if any) defined as follows:

  s

  float

  d

  double

  c

  MKL_Complex8

  z

  MKL_Complex16

• <matrix type> defined as follows:

  Value of <matrix type>		Matrix format	Inner linear system solver used by Extended Eigensolver
  sy	(symmetric real)	Dense	LAPACK dense solvers
  he	(Hermitian complex)
  sb	(symmetric banded real)	Banded-LAPACK	Internal banded solver
  hb	(Hermitian banded complex)
  scsr	(symmetric real)	Compressed sparse row	PARDISO solver
  hcsr	(Hermitian complex)
  s	(symmetric real)	Reverse communications interfaces	User defined
  h	(Hermitian complex)

• <type of eigenvalue problem> is:

  gv

  generalized eigenvalue problem

  ev

  standard eigenvalue problem

For example, sfeast_scsrev is a single-precision routine with a symmetric real matrix stored in sparse compressed-row format for a standard eigenvalue problem, and zfeast_hrci is a complex double-precision routine with a Hermitian matrix using the reverse communication interface.

Note that:

• ? can be s or d if a matrix is real symmetric: <matrix type> is sy, sb, or scsr.

• ? can be c or z if a matrix is complex Hermitian: <matrix type> is he, hb, or hcsr.

• ? can be c or z if the Extended Eigensolver RCI interface is used for solving a complex Hermitian problem.

• ? can be s or d if the Extended Eigensolver RCI interface is used for solving a real symmetric problem.