1 *> \brief \b SLA_GERPVGRW
3 * =========== DOCUMENTATION ===========
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6 * http://www.netlib.org/lapack/explore-html/
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21 * REAL FUNCTION SLA_GERPVGRW( N, NCOLS, A, LDA, AF, LDAF )
23 * .. Scalar Arguments ..
24 * INTEGER N, NCOLS, LDA, LDAF
26 * .. Array Arguments ..
27 * REAL A( LDA, * ), AF( LDAF, * )
36 *> SLA_GERPVGRW computes the reciprocal pivot growth factor
37 *> norm(A)/norm(U). The "max absolute element" norm is used. If this is
38 *> much less than 1, the stability of the LU factorization of the
39 *> (equilibrated) matrix A could be poor. This also means that the
40 *> solution X, estimated condition numbers, and error bounds could be
50 *> The number of linear equations, i.e., the order of the
57 *> The number of columns of the matrix A. NCOLS >= 0.
62 *> A is REAL array, dimension (LDA,N)
63 *> On entry, the N-by-N matrix A.
69 *> The leading dimension of the array A. LDA >= max(1,N).
74 *> AF is REAL array, dimension (LDAF,N)
75 *> The factors L and U from the factorization
76 *> A = P*L*U as computed by SGETRF.
82 *> The leading dimension of the array AF. LDAF >= max(1,N).
88 *> \author Univ. of Tennessee
89 *> \author Univ. of California Berkeley
90 *> \author Univ. of Colorado Denver
93 *> \date November 2011
95 *> \ingroup realGEcomputational
97 * =====================================================================
98 REAL FUNCTION SLA_GERPVGRW( N, NCOLS, A, LDA, AF, LDAF )
100 * -- LAPACK computational routine (version 3.4.0) --
101 * -- LAPACK is a software package provided by Univ. of Tennessee, --
102 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
105 * .. Scalar Arguments ..
106 INTEGER N, NCOLS, LDA, LDAF
108 * .. Array Arguments ..
109 REAL A( LDA, * ), AF( LDAF, * )
112 * =====================================================================
114 * .. Local Scalars ..
116 REAL AMAX, UMAX, RPVGRW
118 * .. Intrinsic Functions ..
119 INTRINSIC ABS, MAX, MIN
121 * .. Executable Statements ..
129 AMAX = MAX( ABS( A( I, J ) ), AMAX )
132 UMAX = MAX( ABS( AF( I, J ) ), UMAX )
134 IF ( UMAX /= 0.0 ) THEN
135 RPVGRW = MIN( AMAX / UMAX, RPVGRW )
138 SLA_GERPVGRW = RPVGRW