 LAPACK  3.8.0 LAPACK: Linear Algebra PACKage

## ◆ zla_gerpvgrw()

 double precision function zla_gerpvgrw ( integer N, integer NCOLS, complex*16, dimension( lda, * ) A, integer LDA, complex*16, dimension( ldaf, * ) AF, integer LDAF )

ZLA_GERPVGRW multiplies a square real matrix by a complex matrix.

Purpose:
``` ZLA_GERPVGRW computes the reciprocal pivot growth factor
norm(A)/norm(U). The "max absolute element" norm is used. If this is
much less than 1, the stability of the LU factorization of the
(equilibrated) matrix A could be poor. This also means that the
solution X, estimated condition numbers, and error bounds could be
unreliable.```
Parameters
 [in] N ``` N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0.``` [in] NCOLS ``` NCOLS is INTEGER The number of columns of the matrix A. NCOLS >= 0.``` [in] A ``` A is COMPLEX*16 array, dimension (LDA,N) On entry, the N-by-N matrix A.``` [in] LDA ``` LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).``` [in] AF ``` AF is COMPLEX*16 array, dimension (LDAF,N) The factors L and U from the factorization A = P*L*U as computed by ZGETRF.``` [in] LDAF ``` LDAF is INTEGER The leading dimension of the array AF. LDAF >= max(1,N).```
Date
June 2016

Definition at line 102 of file zla_gerpvgrw.f.

102 *
103 * -- LAPACK computational routine (version 3.7.0) --
104 * -- LAPACK is a software package provided by Univ. of Tennessee, --
105 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
106 * June 2016
107 *
108 * .. Scalar Arguments ..
109  INTEGER n, ncols, lda, ldaf
110 * ..
111 * .. Array Arguments ..
112  COMPLEX*16 a( lda, * ), af( ldaf, * )
113 * ..
114 *
115 * =====================================================================
116 *
117 * .. Local Scalars ..
118  INTEGER i, j
119  DOUBLE PRECISION amax, umax, rpvgrw
120  COMPLEX*16 zdum
121 * ..
122 * .. Intrinsic Functions ..
123  INTRINSIC max, min, abs, REAL, dimag
124 * ..
125 * .. Statement Functions ..
126  DOUBLE PRECISION cabs1
127 * ..
128 * .. Statement Function Definitions ..
129  cabs1( zdum ) = abs( dble( zdum ) ) + abs( dimag( zdum ) )
130 * ..
131 * .. Executable Statements ..
132 *
133  rpvgrw = 1.0d+0
134
135  DO j = 1, ncols
136  amax = 0.0d+0
137  umax = 0.0d+0
138  DO i = 1, n
139  amax = max( cabs1( a( i, j ) ), amax )
140  END DO
141  DO i = 1, j
142  umax = max( cabs1( af( i, j ) ), umax )
143  END DO
144  IF ( umax /= 0.0d+0 ) THEN
145  rpvgrw = min( amax / umax, rpvgrw )
146  END IF
147  END DO
148  zla_gerpvgrw = rpvgrw
double precision function zla_gerpvgrw(N, NCOLS, A, LDA, AF, LDAF)
ZLA_GERPVGRW multiplies a square real matrix by a complex matrix.
Definition: zla_gerpvgrw.f:102
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