Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

Extended Eigensolver Input Parameters

The input parameters for Extended Eigensolver routines are contained in an
integer
array named
fpm
. To call the Extended Eigensolver interfaces, this array should be initialized using the routine
feastinit
.
Parameter
Default
Description
fpm
(1)
0
Specifies whether Extended Eigensolver routines print runtime status.
fpm
(1)
=0
Extended Eigensolver routines do not generate runtime messages at all.
fpm
(1)
=1
Extended Eigensolver routines print runtime status to the screen.
fpm
(2)
8
The number of contour points
N
e
= 8
(see the description of FEAST algorithm). Must be one of {3,4,5,6,8,10,12,16,20,24,32,40,48}.
fpm
(3)
12
Error trace double precision stopping criteria
ε
(
ε
= 10
-
fpm
(3)
) .
fpm
(4)
20
Maximum number of Extended Eigensolver refinement loops allowed. If no convergence is reached within
fpm
(4)
refinement loops, Extended Eigensolver routines return
info
=2.
fpm
(5)
0
User initial subspace. If
fpm
(5)
=0 then Extended Eigensolver routines generate initial subspace, if
fpm
(5)
=1 the user supplied initial subspace is used.
fpm
(6)
0
Extended Eigensolver stopping test.
fpm
(6)
=0
Extended Eigensolvers are stopped if this residual stopping test is satisfied:
  • generalized eigenvalue problem:
  • standard eigenvalue problem:
where
mode
is the total number of eigenvalues found in the search interval and
ε
= 10
-
fpm
(7)
for real and complex or
ε
= 10
-
fpm
(3)
for double precision and double complex.
fpm
(6)
=1
Extended Eigensolvers are stopped if this trace stopping test is satisfied:
,
where
trace
j
denotes the sum of all eigenvalues found in the search interval [
emin
,
emax
] at the
j
-th Extended Eigensolver iteration:
.
fpm
(7)
5
Error trace single precision stopping criteria (10
-
fpm
(7)
) .
fpm
(14)
0
fpm
(14)
=0
Standard use for Extended Eigensolver routines.
fpm
(14)
=1
Non-standard use for Extended Eigensolver routines: return the computed eigenvectors subspace after one single contour integration.
fpm
(27)
0
Specifies whether Extended Eigensolver rout