sp_ienv(3P) Sun Performance Library sp_ienv(3P)NAMEsp_ienv - called by SuperLU routines to choose machine dependent param‐
eters for the local environment. See ISPEC for a description of the
parameters.
SYNOPSIS
#include <sunperf.h>
int sp_ienv(int ispec);
long sp_ienv_64(long ispec);
PURPOSEsp_ienv provides a set of parameters which should give good, but not
optimal, performance on many of the currently available computers.
Users are encouraged to modify this subroutine to set the tuning
parameters for their particular machine using the option and problem
size information in the arguments.
ARGUMENTS
ISPEC (input)
Specifies the parameter to be returned by sp_ienv.
= 1: the panel size w; a panel consists of w consecutive col‐
umns of matrix A in the process of Gaussian elimination. The
best value depends on machine's cache characters.
= 2: the relaxation parameter relax; if the number of nodes
(columns) in a subtree of the elimination tree is less than
relax, this subtree is considered as one supernode, regard‐
less of their row structures.
= 3: the maximum size for a supernode;
= 4: the minimum row dimension for 2-D blocking to be used;
= 5: the minimum column dimension for 2-D blocking to be
used;
= 6: the estimated fills factor for L and U, compared with A;
int sp_ienv (output)
>= 0: the value of the parameter specified by ISPEC
< 0: if SP_IENV = -k, the k-th argument had an illegal
value.
COPYRIGHT
Copyright (c) 2003, The Regents of the University of California,
through Lawrence Berkeley National Laboratory (subject to receipt of
any required approvals from U.S. Dept. of Energy)
SEE ALSO
http://crd.lbl.gov/~xiaoye/SuperLU/
James W. Demmel, Stanley C. Eisenstat, John R. Gilbert, Xiaoye S. Li
and Joseph W. H. Liu, "A supernodal approach to sparse partial pivot‐
ing", SIAM J. Matrix Analysis and Applications, Vol. 20, Num. 3, 1999,
pp. 720-755.
6 Mar 2009 sp_ienv(3P)
