dlatb5()

subroutine dlatb5	(	character*3	path,
		integer	imat,
		integer	n,
		character	type,
		integer	kl,
		integer	ku,
		double precision	anorm,
		integer	mode,
		double precision	cndnum,
		character	dist )

DLATB5

Purpose:

!>
!> DLATB5 sets parameters for the matrix generator based on the type
!> of matrix to be generated.
!> 

Parameters

[in]	PATH	!> PATH is CHARACTER*3 !> The LAPACK path name. !>
[in]	IMAT	!> IMAT is INTEGER !> An integer key describing which matrix to generate for this !> path. !>
[in]	N	!> N is INTEGER !> The number of rows and columns in the matrix to be generated. !>
[out]	TYPE	!> TYPE is CHARACTER*1 !> The type of the matrix to be generated: !> = 'S': symmetric matrix !> = 'P': symmetric positive (semi)definite matrix !> = 'N': nonsymmetric matrix !>
[out]	KL	!> KL is INTEGER !> The lower band width of the matrix to be generated. !>
[out]	KU	!> KU is INTEGER !> The upper band width of the matrix to be generated. !>
[out]	ANORM	!> ANORM is DOUBLE PRECISION !> The desired norm of the matrix to be generated. The diagonal !> matrix of singular values or eigenvalues is scaled by this !> value. !>
[out]	MODE	!> MODE is INTEGER !> A key indicating how to choose the vector of eigenvalues. !>
[out]	CNDNUM	!> CNDNUM is DOUBLE PRECISION !> The desired condition number. !>
[out]	DIST	!> DIST is CHARACTER*1 !> The type of distribution to be used by the random number !> generator. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 112 of file dlatb5.f.

*
*  -- LAPACK test routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      DOUBLE PRECISION   ANORM, CNDNUM
      INTEGER            IMAT, KL, KU, MODE, N
      CHARACTER          DIST, TYPE
      CHARACTER*3        PATH
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      DOUBLE PRECISION   SHRINK, TENTH
      parameter( shrink = 0.25d0, tenth = 0.1d+0 )
      DOUBLE PRECISION   ONE
      parameter( one = 1.0d+0 )
      DOUBLE PRECISION   TWO
      parameter( two = 2.0d+0 )
*     ..
*     .. Local Scalars ..
      DOUBLE PRECISION   BADC1, BADC2, EPS, LARGE, SMALL
      LOGICAL            FIRST
      CHARACTER*2        C2
*     ..
*     .. External Functions ..
      DOUBLE PRECISION   DLAMCH
      EXTERNAL           dlamch
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          max, sqrt
*     ..
*     .. Save statement ..
      SAVE               eps, small, large, badc1, badc2, first
*     ..
*     .. Data statements ..
      DATA               first / .true. /
*     ..
*     .. Executable Statements ..
*
*     Set some constants for use in the subroutine.
*
      IF( first ) THEN
         first = .false.
         eps = dlamch( 'Precision' )
         badc2 = tenth / eps
         badc1 = sqrt( badc2 )
         small = dlamch( 'Safe minimum' )
         large = one / small
         small = shrink*( small / eps )
         large = one / small
      END IF
*
      c2 = path( 2: 3 )
*
*     Set some parameters
*
      dist = 'S'
      mode = 3
*
*     Set TYPE, the type of matrix to be generated.
*
      TYPE = c2( 1: 1 )
*
*     Set the lower and upper bandwidths.
*
      IF( imat.EQ.1 ) THEN
         kl = 0
      ELSE
         kl = max( n-1, 0 )
      END IF
      ku = kl
*
*     Set the condition number and norm.etc
*
      IF( imat.EQ.3 ) THEN
         cndnum = 1.0d12
         mode = 2
      ELSE IF( imat.EQ.4 ) THEN
         cndnum = 1.0d12
         mode = 1
      ELSE IF( imat.EQ.5 ) THEN
         cndnum = 1.0d12
         mode = 3
      ELSE IF( imat.EQ.6 ) THEN
         cndnum = badc1
      ELSE IF( imat.EQ.7 ) THEN
         cndnum = badc2
      ELSE
         cndnum = two
      END IF
*
      IF( imat.EQ.8 ) THEN
         anorm = small
      ELSE IF( imat.EQ.9 ) THEN
         anorm = large
      ELSE
         anorm = one
      END IF
*
      IF( n.LE.1 )
     $   cndnum = one
*
      RETURN
*
*     End of DLATB5
*

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