sp_ienv (3p)

Name

sp_ienv - 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);

Description

Oracle Solaris Studio Performance Library                          sp_ienv(3P)



NAME
       sp_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);


PURPOSE
       sp_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.


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.



                                  7 Nov 2015                       sp_ienv(3P)