forked from bartvdbraak/blender
66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
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/*
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* File name: sp_ienv.c
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* History: Modified from lapack routine ILAENV
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*/
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#include "ssp_defs.h"
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#include "util.h"
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int
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sp_ienv(int ispec)
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{
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/*
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Purpose
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=======
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sp_ienv() is inquired to choose machine-dependent parameters for the
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local environment. See ISPEC for a description of the parameters.
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This version provides a set of parameters which should give good,
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but not optimal, performance on many of the currently available
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computers. Users are encouraged to modify this subroutine to set
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the tuning parameters for their particular machine using the option
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and problem size information in the arguments.
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Arguments
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=========
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ISPEC (input) int
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Specifies the parameter to be returned as the value of SP_IENV.
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= 1: the panel size w; a panel consists of w consecutive
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columns of matrix A in the process of Gaussian elimination.
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The best value depends on machine's cache characters.
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= 2: the relaxation parameter relax; if the number of
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nodes (columns) in a subtree of the elimination tree is less
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than relax, this subtree is considered as one supernode,
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regardless of their row structures.
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= 3: the maximum size for a supernode;
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= 4: the minimum row dimension for 2-D blocking to be used;
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= 5: the minimum column dimension for 2-D blocking to be used;
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= 6: the estimated fills factor for L and U, compared with A;
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(SP_IENV) (output) int
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>= 0: the value of the parameter specified by ISPEC
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< 0: if SP_IENV = -k, the k-th argument had an illegal value.
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=====================================================================
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*/
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int i;
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switch (ispec) {
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case 1: return (10);
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case 2: return (5);
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case 3: return (100);
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case 4: return (200);
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case 5: return (40);
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case 6: return (20);
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}
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/* Invalid value for ISPEC */
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i = 1;
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xerbla_("sp_ienv", &i);
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return 0;
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} /* sp_ienv_ */
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