Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

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Extended Eigensolver Input Parameters

The input parameters for Extended Eigensolver routines are contained in an
MKL_INT
 array named
fpm
. To call the Extended Eigensolver interfaces, this array should be initialized using the routine
feastinit
.
Parameter
Default
Description
fpm
[0]
0
Specifies whether Extended Eigensolver routines print runtime status.
fpm
[0]
=0
Extended Eigensolver routines do not generate runtime messages at all.
fpm
[0]
=1
Extended Eigensolver routines print runtime status to the screen.
fpm
[1]
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
[2]
12
Error trace double precision stopping criteria
ε
 (
ε
 = 10
-
fpm
[2]
) .
fpm
[3]
20
Maximum number of Extended Eigensolver refinement loops allowed. If no convergence is reached within
fpm
[3]
 refinement loops, Extended Eigensolver routines return
info
=2.
fpm
[4]
0
User initial subspace. If
fpm
[4]
=0 then Extended Eigensolver routines generate initial subspace, if
fpm
[4]
=1 the user supplied initial subspace is used.
fpm
[5]
0
Extended Eigensolver stopping test.
fpm
[5]
=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
[6]
 for real and complex or
ε
 = 10
-
fpm
[2]
 for double precision and double complex.
fpm
[5]
=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
[6]
5
Error trace single precision stopping criteria (10
-
fpm
[6]
) .
fpm
[13]
0
fpm
[13]
=0
Standard use for Extended Eigensolver routines.
fpm
[13]
=1
Non-standard use for Extended Eigensolver routines: return the computed eigenvectors subspace after one single contour integration.
fpm
[26]
0
Specifies whether Extended Eigensolver routines check input matrices (applies to CSR format only).
fpm
[26]
=0
Extended Eigensolver routines do not check input matrices.
fpm
[26]
=1
Extended Eigensolver routines check input matrices.
fpm
[27]
0
Check if matrix
B
 is positive definite. Set
fpm
[27]
= 1
 to check if
B
 is positive definite.
fpm
[29]
 to
fpm
[62]
-
Reserved for future use.
fpm
[63]
0
Use the
Intel® oneAPI Math Kernel Library
 PARDISO solver with the user-defined PARDISO
iparm
 array settings.
This option can only be used by Extended Eigensolver Predefined Interfaces for Sparse Matrices.
fpm
[63]
=0
Extended Eigensolver routines use the
Intel® oneAPI Math Kernel Library
 PARDISO default
iparm
 settings defined by calling the
pardisoinit
 subroutine.
fpm
[63]
=1
The values from
fpm
[64]
 to
fpm
[127]
 correspond to
iparm
[0]
 to
iparm
[63]
 respectively according to the formula
fpm
[64 +
i
]
=
iparm
[
i
]
 for
i
 =
0, 1, ..., 63
.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.