LAPACK 3.12.0 LAPACK: Linear Algebra PACKage
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xlaenv.f
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1*> \brief \b XLAENV
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8* Definition:
9* ===========
10*
11* SUBROUTINE XLAENV( ISPEC, NVALUE )
12*
13* .. Scalar Arguments ..
14* INTEGER ISPEC, NVALUE
15* ..
16*
17*
18*> \par Purpose:
19* =============
20*>
21*> \verbatim
22*>
23*> XLAENV sets certain machine- and problem-dependent quantities
24*> which will later be retrieved by ILAENV.
25*> \endverbatim
26*
27* Arguments:
28* ==========
29*
30*> \param[in] ISPEC
31*> \verbatim
32*> ISPEC is INTEGER
33*> Specifies the parameter to be set in the COMMON array IPARMS.
34*> = 1: the optimal blocksize; if this value is 1, an unblocked
35*> algorithm will give the best performance.
36*> = 2: the minimum block size for which the block routine
37*> should be used; if the usable block size is less than
38*> this value, an unblocked routine should be used.
39*> = 3: the crossover point (in a block routine, for N less
40*> than this value, an unblocked routine should be used)
41*> = 4: the number of shifts, used in the nonsymmetric
42*> eigenvalue routines
43*> = 5: the minimum column dimension for blocking to be used;
44*> rectangular blocks must have dimension at least k by m,
45*> where k is given by ILAENV(2,...) and m by ILAENV(5,...)
46*> = 6: the crossover point for the SVD (when reducing an m by n
47*> matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds
48*> this value, a QR factorization is used first to reduce
49*> the matrix to a triangular form)
50*> = 7: the number of processors
51*> = 8: another crossover point, for the multishift QR and QZ
52*> methods for nonsymmetric eigenvalue problems.
53*> = 9: maximum size of the subproblems at the bottom of the
54*> computation tree in the divide-and-conquer algorithm
55*> (used by xGELSD and xGESDD)
56*> =10: ieee NaN arithmetic can be trusted not to trap
57*> =11: infinity arithmetic can be trusted not to trap
58*> 12 <= ISPEC <= 16:
59*> xHSEQR or one of its subroutines,
60*> see IPARMQ for detailed explanation
61*> \endverbatim
62*>
63*> \param[in] NVALUE
64*> \verbatim
65*> NVALUE is INTEGER
66*> The value of the parameter specified by ISPEC.
67*> \endverbatim
68*
69* Authors:
70* ========
71*
72*> \author Univ. of Tennessee
73*> \author Univ. of California Berkeley
74*> \author Univ. of Colorado Denver
75*> \author NAG Ltd.
76*
77*> \ingroup aux_eig
78*
79* =====================================================================
80 SUBROUTINE xlaenv( ISPEC, NVALUE )
81*
82* -- LAPACK test routine --
83* -- LAPACK is a software package provided by Univ. of Tennessee, --
84* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
85*
86* .. Scalar Arguments ..
87 INTEGER ISPEC, NVALUE
88* ..
89*
90* =====================================================================
91*
92* .. Arrays in Common ..
93 INTEGER IPARMS( 100 )
94* ..
95* .. Common blocks ..
96 COMMON / claenv / iparms
97* ..
98* .. Save statement ..
99 SAVE / claenv /
100* ..
101* .. Executable Statements ..
102*
103 IF( ispec.GE.1 .AND. ispec.LE.16 ) THEN
104 iparms( ispec ) = nvalue
105 END IF
106*
107 RETURN
108*
109* End of XLAENV
110*
111 END
subroutine xlaenv(ispec, nvalue)
XLAENV
Definition xlaenv.f:81