SUBROUTINE DLASCL( TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO ) ! ! -- 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