zqrt13()

subroutine zqrt13	(	integer	SCALE,
		integer	M,
		integer	N,
		complex*16, dimension( lda, * )	A,
		integer	LDA,
		double precision	NORMA,
		integer, dimension( 4 )	ISEED
	)

ZQRT13

Purpose:

 ZQRT13 generates a full-rank matrix that may be scaled to have large
 or small norm.

Parameters

[in]	SCALE	SCALE is INTEGER SCALE = 1: normally scaled matrix SCALE = 2: matrix scaled up SCALE = 3: matrix scaled down
[in]	M	M is INTEGER The number of rows of the matrix A.
[in]	N	N is INTEGER The number of columns of A.
[out]	A	A is COMPLEX*16 array, dimension (LDA,N) The M-by-N matrix A.
[in]	LDA	LDA is INTEGER The leading dimension of the array A.
[out]	NORMA	NORMA is DOUBLE PRECISION The one-norm of A.
[in,out]	ISEED	ISEED is integer array, dimension (4) Seed for random number generator

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date

December 2016

Definition at line 93 of file zqrt13.f.

*
*  -- LAPACK test routine (version 3.7.0) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     December 2016
*
*     .. Scalar Arguments ..
      INTEGER            LDA, M, N, SCALE
      DOUBLE PRECISION   NORMA
*     ..
*     .. Array Arguments ..
      INTEGER            ISEED( 4 )
      COMPLEX*16         A( LDA, * )
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      DOUBLE PRECISION   ONE
      parameter( one = 1.0d0 )
*     ..
*     .. Local Scalars ..
      INTEGER            INFO, J
      DOUBLE PRECISION   BIGNUM, SMLNUM
*     ..
*     .. External Functions ..
      DOUBLE PRECISION   DLAMCH, DZASUM, ZLANGE
      EXTERNAL           dlamch, dzasum, zlange
*     ..
*     .. External Subroutines ..
      EXTERNAL           dlabad, zlarnv, zlascl
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          dble, dcmplx, sign
*     ..
*     .. Local Arrays ..
      DOUBLE PRECISION   DUMMY( 1 )
*     ..
*     .. Executable Statements ..
*
      IF( m.LE.0 .OR. n.LE.0 )
     $   RETURN
*
*     benign matrix
*
      DO 10 j = 1, n
         CALL zlarnv( 2, iseed, m, a( 1, j ) )
         IF( j.LE.m ) THEN
            a( j, j ) = a( j, j ) + dcmplx( sign( dzasum( m, a( 1, j ),
     $                  1 ), dble( a( j, j ) ) ) )
         END IF
   10 CONTINUE
*
*     scaled versions
*
      IF( scale.NE.1 ) THEN
         norma = zlange( 'Max', m, n, a, lda, dummy )
         smlnum = dlamch( 'Safe minimum' )
         bignum = one / smlnum
         CALL dlabad( smlnum, bignum )
         smlnum = smlnum / dlamch( 'Epsilon' )
         bignum = one / smlnum
*
         IF( scale.EQ.2 ) THEN
*
*           matrix scaled up
*
            CALL zlascl( 'General', 0, 0, norma, bignum, m, n, a, lda,
     $                   info )
         ELSE IF( scale.EQ.3 ) THEN
*
*           matrix scaled down
*
            CALL zlascl( 'General', 0, 0, norma, smlnum, m, n, a, lda,
     $                   info )
         END IF
      END IF
*
      norma = zlange( 'One-norm', m, n, a, lda, dummy )
      RETURN
*
*     End of ZQRT13
*

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