diff options
Diffstat (limited to 'src/fortran/lapack/dlascl.f')
| -rw-r--r-- | src/fortran/lapack/dlascl.f | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/src/fortran/lapack/dlascl.f b/src/fortran/lapack/dlascl.f new file mode 100644 index 0000000..7a7a78f --- /dev/null +++ b/src/fortran/lapack/dlascl.f @@ -0,0 +1,267 @@ + 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 |