*> \brief \b CLASCL multiplies a general rectangular matrix by a real scalar defined as cto/cfrom. * * =========== DOCUMENTATION =========== * * Online html documentation available at * http://www.netlib.org/lapack/explore-html/ * *> \htmlonly *> Download CLASCL + dependencies *> *> [TGZ] *> *> [ZIP] *> *> [TXT] *> \endhtmlonly * * Definition: * =========== * * SUBROUTINE CLASCL( TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO ) * * .. Scalar Arguments .. * CHARACTER TYPE * INTEGER INFO, KL, KU, LDA, M, N * REAL CFROM, CTO * .. * .. Array Arguments .. * COMPLEX A( LDA, * ) * .. * * *> \par Purpose: * ============= *> *> \verbatim *> *> CLASCL multiplies the M by N complex 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. *> \endverbatim * * Arguments: * ========== * *> \param[in] TYPE *> \verbatim *> TYPE is 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. See CGBTRF for storage details. *> \endverbatim *> *> \param[in] KL *> \verbatim *> KL is INTEGER *> The lower bandwidth of A. Referenced only if TYPE = 'B', *> 'Q' or 'Z'. *> \endverbatim *> *> \param[in] KU *> \verbatim *> KU is INTEGER *> The upper bandwidth of A. Referenced only if TYPE = 'B', *> 'Q' or 'Z'. *> \endverbatim *> *> \param[in] CFROM *> \verbatim *> CFROM is REAL *> \endverbatim *> *> \param[in] CTO *> \verbatim *> CTO is REAL *> *> 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. *> \endverbatim *> *> \param[in] M *> \verbatim *> M is INTEGER *> The number of rows of the matrix A. M >= 0. *> \endverbatim *> *> \param[in] N *> \verbatim *> N is INTEGER *> The number of columns of the matrix A. N >= 0. *> \endverbatim *> *> \param[in,out] A *> \verbatim *> A is COMPLEX array, dimension (LDA,N) *> The matrix to be multiplied by CTO/CFROM. See TYPE for the *> storage type. *> \endverbatim *> *> \param[in] LDA *> \verbatim *> LDA is INTEGER *> The leading dimension of the array A. *> If TYPE = 'G', 'L', 'U', 'H', LDA >= max(1,M); *> TYPE = 'B', LDA >= KL+1; *> TYPE = 'Q', LDA >= KU+1; *> TYPE = 'Z', LDA >= 2*KL+KU+1. *> \endverbatim *> *> \param[out] INFO *> \verbatim *> INFO is INTEGER *> 0 - successful exit *> <0 - if INFO = -i, the i-th argument had an illegal value. *> \endverbatim * * Authors: * ======== * *> \author Univ. of Tennessee *> \author Univ. of California Berkeley *> \author Univ. of Colorado Denver *> \author NAG Ltd. * *> \ingroup complexOTHERauxiliary * * ===================================================================== SUBROUTINE CLASCL( TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO ) * * -- LAPACK auxiliary routine -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- * * .. Scalar Arguments .. CHARACTER TYPE INTEGER INFO, KL, KU, LDA, M, N REAL CFROM, CTO * .. * .. Array Arguments .. COMPLEX A( LDA, * ) * .. * * ===================================================================== * * .. Parameters .. REAL ZERO, ONE PARAMETER ( ZERO = 0.0E0, ONE = 1.0E0 ) * .. * .. Local Scalars .. LOGICAL DONE INTEGER I, ITYPE, J, K1, K2, K3, K4 REAL BIGNUM, CFROM1, CFROMC, CTO1, CTOC, MUL, SMLNUM * .. * .. External Functions .. LOGICAL LSAME, SISNAN REAL SLAMCH EXTERNAL LSAME, SLAMCH, SISNAN * .. * .. 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 .OR. SISNAN(CFROM) ) THEN INFO = -4 ELSE IF( SISNAN(CTO) ) THEN INFO = -5 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( 'CLASCL', -INFO ) RETURN END IF * * Quick return if possible * IF( N.EQ.0 .OR. M.EQ.0 ) \$ RETURN * * Get machine parameters * SMLNUM = SLAMCH( 'S' ) BIGNUM = ONE / SMLNUM * CFROMC = CFROM CTOC = CTO * 10 CONTINUE CFROM1 = CFROMC*SMLNUM IF( CFROM1.EQ.CFROMC ) THEN ! CFROMC is an inf. Multiply by a correctly signed zero for ! finite CTOC, or a NaN if CTOC is infinite. MUL = CTOC / CFROMC DONE = .TRUE. CTO1 = CTOC ELSE CTO1 = CTOC / BIGNUM IF( CTO1.EQ.CTOC ) THEN ! CTOC is either 0 or an inf. In both cases, CTOC itself ! serves as the correct multiplication factor. MUL = CTOC DONE = .TRUE. CFROMC = ONE ELSE 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. IF (MUL .EQ. ONE) \$ RETURN END IF 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 CLASCL * END