1 *> \brief \b DLA_GERPVGRW
3 * =========== DOCUMENTATION ===========
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
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21 * DOUBLE PRECISION FUNCTION DLA_GERPVGRW( N, NCOLS, A, LDA, AF,
24 * .. Scalar Arguments ..
25 * INTEGER N, NCOLS, LDA, LDAF
27 * .. Array Arguments ..
28 * DOUBLE PRECISION A( LDA, * ), AF( LDAF, * )
38 *> DLA_GERPVGRW computes the reciprocal pivot growth factor
39 *> norm(A)/norm(U). The "max absolute element" norm is used. If this is
40 *> much less than 1, the stability of the LU factorization of the
41 *> (equilibrated) matrix A could be poor. This also means that the
42 *> solution X, estimated condition numbers, and error bounds could be
52 *> The number of linear equations, i.e., the order of the
59 *> The number of columns of the matrix A. NCOLS >= 0.
64 *> A is DOUBLE PRECISION array, dimension (LDA,N)
65 *> On entry, the N-by-N matrix A.
71 *> The leading dimension of the array A. LDA >= max(1,N).
76 *> AF is DOUBLE PRECISION array, dimension (LDAF,N)
77 *> The factors L and U from the factorization
78 *> A = P*L*U as computed by DGETRF.
84 *> The leading dimension of the array AF. LDAF >= max(1,N).
90 *> \author Univ. of Tennessee
91 *> \author Univ. of California Berkeley
92 *> \author Univ. of Colorado Denver
95 *> \date November 2011
97 *> \ingroup doubleGEcomputational
99 * =====================================================================
100 DOUBLE PRECISION FUNCTION DLA_GERPVGRW( N, NCOLS, A, LDA, AF,
103 * -- LAPACK computational routine (version 3.4.0) --
104 * -- LAPACK is a software package provided by Univ. of Tennessee, --
105 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
108 * .. Scalar Arguments ..
109 INTEGER N, NCOLS, LDA, LDAF
111 * .. Array Arguments ..
112 DOUBLE PRECISION A( LDA, * ), AF( LDAF, * )
115 * =====================================================================
117 * .. Local Scalars ..
119 DOUBLE PRECISION AMAX, UMAX, RPVGRW
121 * .. Intrinsic Functions ..
122 INTRINSIC ABS, MAX, MIN
124 * .. Executable Statements ..
132 AMAX = MAX( ABS( A( I, J ) ), AMAX )
135 UMAX = MAX( ABS( AF( I, J ) ), UMAX )
137 IF ( UMAX /= 0.0D+0 ) THEN
138 RPVGRW = MIN( AMAX / UMAX, RPVGRW )
141 DLA_GERPVGRW = RPVGRW