SUBROUTINE DLASCL( TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO ) 15,2
!
! -- LAPACK auxiliary routine (version 3.1) --
! Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
! November 2006
!
! .. Scalar Arguments ..
CHARACTER TYPE
INTEGER INFO, KL, KU, LDA, M, N
DOUBLE PRECISION CFROM, CTO
! ..
! .. Array Arguments ..
DOUBLE PRECISION A( LDA, * )
! ..
!
! Purpose
! =======
!
! DLASCL multiplies the M by N real matrix A by the real scalar
! CTO/CFROM. This is done without over/underflow as long as the final
! result CTO*A(I,J)/CFROM does not over/underflow. TYPE specifies that
! A may be full, upper triangular, lower triangular, upper Hessenberg,
! or banded.
!
! Arguments
! =========
!
! TYPE (input) CHARACTER*1
! TYPE indices the storage type of the input matrix.
! = 'G': A is a full matrix.
! = 'L': A is a lower triangular matrix.
! = 'U': A is an upper triangular matrix.
! = 'H': A is an upper Hessenberg matrix.
! = 'B': A is a symmetric band matrix with lower bandwidth KL
! and upper bandwidth KU and with the only the lower
! half stored.
! = 'Q': A is a symmetric band matrix with lower bandwidth KL
! and upper bandwidth KU and with the only the upper
! half stored.
! = 'Z': A is a band matrix with lower bandwidth KL and upper
! bandwidth KU.
!
! KL (input) INTEGER
! The lower bandwidth of A. Referenced only if TYPE = 'B',
! 'Q' or 'Z'.
!
! KU (input) INTEGER
! The upper bandwidth of A. Referenced only if TYPE = 'B',
! 'Q' or 'Z'.
!
! CFROM (input) DOUBLE PRECISION
! CTO (input) DOUBLE PRECISION
! The matrix A is multiplied by CTO/CFROM. A(I,J) is computed
! without over/underflow if the final result CTO*A(I,J)/CFROM
! can be represented without over/underflow. CFROM must be
! nonzero.
!
! M (input) INTEGER
! The number of rows of the matrix A. M >= 0.
!
! N (input) INTEGER
! The number of columns of the matrix A. N >= 0.
!
! A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
! The matrix to be multiplied by CTO/CFROM. See TYPE for the
! storage type.
!
! LDA (input) INTEGER
! The leading dimension of the array A. LDA >= max(1,M).
!
! INFO (output) INTEGER
! 0 - successful exit
! <0 - if INFO = -i, the i-th argument had an illegal value.
!
! =====================================================================
!
! .. Parameters ..
DOUBLE PRECISION ZERO, ONE
PARAMETER ( ZERO = 0.0D0, ONE = 1.0D0 )
! ..
! .. Local Scalars ..
LOGICAL DONE
INTEGER I, ITYPE, J, K1, K2, K3, K4
DOUBLE PRECISION BIGNUM, CFROM1, CFROMC, CTO1, CTOC, MUL, SMLNUM
! ..
! .. External Functions ..
! LOGICAL LSAME
! DOUBLE PRECISION DLAMCH
! EXTERNAL LSAME, DLAMCH
! ..
! .. Intrinsic Functions ..
INTRINSIC ABS, MAX, MIN
! ..
! .. External Subroutines ..
! EXTERNAL XERBLA
! ..
! .. Executable Statements ..
!
! Test the input arguments
!
INFO = 0
!
IF( LSAME( TYPE, 'G' ) ) THEN
ITYPE = 0
ELSE IF( LSAME( TYPE, 'L' ) ) THEN
ITYPE = 1
ELSE IF( LSAME( TYPE, 'U' ) ) THEN
ITYPE = 2
ELSE IF( LSAME( TYPE, 'H' ) ) THEN
ITYPE = 3
ELSE IF( LSAME( TYPE, 'B' ) ) THEN
ITYPE = 4
ELSE IF( LSAME( TYPE, 'Q' ) ) THEN
ITYPE = 5
ELSE IF( LSAME( TYPE, 'Z' ) ) THEN
ITYPE = 6
ELSE
ITYPE = -1
END IF
!
IF( ITYPE.EQ.-1 ) THEN
INFO = -1
ELSE IF( CFROM.EQ.ZERO ) THEN
INFO = -4
ELSE IF( M.LT.0 ) THEN
INFO = -6
ELSE IF( N.LT.0 .OR. ( ITYPE.EQ.4 .AND. N.NE.M ) .OR. &
( ITYPE.EQ.5 .AND. N.NE.M ) ) THEN
INFO = -7
ELSE IF( ITYPE.LE.3 .AND. LDA.LT.MAX( 1, M ) ) THEN
INFO = -9
ELSE IF( ITYPE.GE.4 ) THEN
IF( KL.LT.0 .OR. KL.GT.MAX( M-1, 0 ) ) THEN
INFO = -2
ELSE IF( KU.LT.0 .OR. KU.GT.MAX( N-1, 0 ) .OR. &
( ( ITYPE.EQ.4 .OR. ITYPE.EQ.5 ) .AND. KL.NE.KU ) ) &
THEN
INFO = -3
ELSE IF( ( ITYPE.EQ.4 .AND. LDA.LT.KL+1 ) .OR. &
( ITYPE.EQ.5 .AND. LDA.LT.KU+1 ) .OR. &
( ITYPE.EQ.6 .AND. LDA.LT.2*KL+KU+1 ) ) THEN
INFO = -9
END IF
END IF
!
IF( INFO.NE.0 ) THEN
CALL XERBLA
( 'DLASCL', -INFO )
RETURN
END IF
!
! Quick return if possible
!
IF( N.EQ.0 .OR. M.EQ.0 ) &
RETURN
!
! Get machine parameters
!
SMLNUM = DLAMCH( 'S' )
BIGNUM = ONE / SMLNUM
!
CFROMC = CFROM
CTOC = CTO
!
10 CONTINUE
CFROM1 = CFROMC*SMLNUM
CTO1 = CTOC / BIGNUM
IF( ABS( CFROM1 ).GT.ABS( CTOC ) .AND. CTOC.NE.ZERO ) THEN
MUL = SMLNUM
DONE = .FALSE.
CFROMC = CFROM1
ELSE IF( ABS( CTO1 ).GT.ABS( CFROMC ) ) THEN
MUL = BIGNUM
DONE = .FALSE.
CTOC = CTO1
ELSE
MUL = CTOC / CFROMC
DONE = .TRUE.
END IF
!
IF( ITYPE.EQ.0 ) THEN
!
! Full matrix
!
DO 30 J = 1, N
DO 20 I = 1, M
A( I, J ) = A( I, J )*MUL
20 CONTINUE
30 CONTINUE
!
ELSE IF( ITYPE.EQ.1 ) THEN
!
! Lower triangular matrix
!
DO 50 J = 1, N
DO 40 I = J, M
A( I, J ) = A( I, J )*MUL
40 CONTINUE
50 CONTINUE
!
ELSE IF( ITYPE.EQ.2 ) THEN
!
! Upper triangular matrix
!
DO 70 J = 1, N
DO 60 I = 1, MIN( J, M )
A( I, J ) = A( I, J )*MUL
60 CONTINUE
70 CONTINUE
!
ELSE IF( ITYPE.EQ.3 ) THEN
!
! Upper Hessenberg matrix
!
DO 90 J = 1, N
DO 80 I = 1, MIN( J+1, M )
A( I, J ) = A( I, J )*MUL
80 CONTINUE
90 CONTINUE
!
ELSE IF( ITYPE.EQ.4 ) THEN
!
! Lower half of a symmetric band matrix
!
K3 = KL + 1
K4 = N + 1
DO 110 J = 1, N
DO 100 I = 1, MIN( K3, K4-J )
A( I, J ) = A( I, J )*MUL
100 CONTINUE
110 CONTINUE
!
ELSE IF( ITYPE.EQ.5 ) THEN
!
! Upper half of a symmetric band matrix
!
K1 = KU + 2
K3 = KU + 1
DO 130 J = 1, N
DO 120 I = MAX( K1-J, 1 ), K3
A( I, J ) = A( I, J )*MUL
120 CONTINUE
130 CONTINUE
!
ELSE IF( ITYPE.EQ.6 ) THEN
!
! Band matrix
!
K1 = KL + KU + 2
K2 = KL + 1
K3 = 2*KL + KU + 1
K4 = KL + KU + 1 + M
DO 150 J = 1, N
DO 140 I = MAX( K1-J, K2 ), MIN( K3, K4-J )
A( I, J ) = A( I, J )*MUL
140 CONTINUE
150 CONTINUE
!
END IF
!
IF( .NOT.DONE ) &
GO TO 10
!
RETURN
!
! End of DLASCL
!
END SUBROUTINE DLASCL